Walter F. Dabberdt1 and South Central Coast Cooperative William Viezee2 Aerometric Monitoring Program (SCCCAMP)

Abstract

The SCCCAMP field measurement program, conducted 3 September to 7 October 1985, is the most comprehensive mesoscale photochemical study of its type ever undertaken. The study area encompasses 2 X 104 km2 of coastal and interior south-central California including the Santa Barbara Channel. A review of earlier experimental and analytical studies in the area is followed by the organizational framework and planning for this cooperative program. The experimental design and measurement systems are described. Existing ground-based meteoro- logical and air pollution networks were supplemented by additional surface aerometric stations, dual Doppler radars, rawinsondes, and a network of Doppler acoustic profilers. Airborne measurement platforms included one dual-channel , three aerometric sampling aircraft,3 and a meteorological research aircraft. Gas tracer tests included 4-h releases of three perfluorocarbon gas tracers. Tracer measurements were FIG. 1. Topographic map of SCCCAMP region. made over two-day periods at 50 surface locations and aloft by aircraft with a near-realtime two-trap chromatographic system. Four multi-day The SCCCAMP area has been the focus of intensive at- intensive operational periods (IOP) are described, and illustrative re- mospheric research studies for more than two decades during sults from one IOP are presented when extremely high ozone concen- trations were observed at ground level (230 ppb) and aloft (290 ppb). which numerous meteorological, air pollution, and gas-tracer The availability of the composite data base is indicated. measurement and analysis programs have been conducted. Edinger (1963) used aircraft soundings to investigate the mod- ification of the marine boundary layer (MBL) as it is advected through the Santa Clara River Valley. Baynton et al. (1965) 1. Introduction and background studied the association of low-level inversions at Point Arguello (about 20 km NW of Point Conception) with surface wind and The South Central Coast Cooperative Aerometric Monitoring temperature using 4-1/2 years of rawinsonde data. Lea (1968) Program (SCCCAMP) is a comprehensive experimental study analyzed lower tropospheric ozone profiles from 69 balloon- of boundary-layer dynamics and photochemistry on the meso- borne chemiluminescent sondes launched from Pt. Mugu over 0 scale in the coastal and interior portions of south-central a two-year period; these frequently showed a maximum above California encompassing the Santa Barbara Channel (Fig. 1). the base of the low-level subsidence inversion. Edinger and Intensive surface and bondary-layer measurements were made Wurtele (1971) again used aircraft observations in studying 4 2 over an area of approximately 2 x 10 km during the period MBL structure in the offshore region between Palos Verdes- 3 September to 7 October 1985. The objectives were to in- Catalina Island in the Los Angeles basin and Pt. Conception. vestigate the physical mechanisms that infrequently create ex- Giroux et al. (1974) and Lamb et al. (1978) undertook separate cessive concentrations of photochemical oxidant at ground gas tracer studies using sulfur hexafluoride (SF6) released from level, and to provide a comprehensive data base for develop- the stack of the Ormand Beach Generating Station on the coast ment and evaluation of a mesoscale photochemical simulation near Port Hueneme. Kauper and Niemann (1975) obtained ver- model. Measurements were made continually by surface and tical profiles of ozone and temperature by aircraft in Ventura upper-air networks, while supplemental aircraft, radar, rawin- and Los Angeles Counties in an investigation of ozone trans- sonde, chemical, and gas tracer measurements were made dur- port. Dispersion characteristics of plumes from oil seeps off- ing four intensive operational periods (IOP). shore of Santa Barbara were studied by Maas and Harrison (1977). The structure of coastal stratus was addressed by Lee (1979) who used satellite observations to document terrain ef- fects of the Santa Ynez Mountains. 1 National Center for Atmospheric Research, Boulder, CO 80307 (The National Center for Atmospheric Research is sponsored by the Smith et al. (1983) analyzed meteorological, tracer, and air National Science Foundation). pollution data obtained by Lehrman et al. (1981), Hayden et 2 SRI International, Menlo Park, CA 94025. al. (1981), Schacher et al. (1982) and Zannetti et al. (1981) in 3 The western aerometric aircraft did not return from the evening joint studies conducted during September and October 1980 in flight of October 3, and is presumed to have been lost at sea in the vicinity of San Miguel Island. This review of the SCCCAMP field the offshore and coastal portions of the SCCCAMP region. The measurement program is dedicated to the memory of Joe Detweiler 1980 program consisted of six sets of tracer releases with sup- and Sandy McDonald, pilot and scientist aboard N6726Y. Their porting surface measurements of wind and ozone, pibal ob- warmth, friendship and contributions will not be forgotten. servations, and aircraft aerometric measurements. Smith et al. © 1987 American Meteorological Society suggested the existence of two significant atmospheric circu-

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Unauthenticated | Downloaded 10/04/21 05:12 AM UTC Bulletin American Meteorological Society 1099 lations in the Santa Barbara MBL: a large nocturnal closed cyclonic mid-channel eddy extending east-west from Ventura to Gaviota and north-south from the Santa Barbara coastline to the Channel Islands; and a daytime cyclonic Gaviota eddy in the lee of Pt. Conception. Figure 2 illustrates surface stream- lines for these two circulations constructed by Smith et al. from most frequent wind directions observed at 2-h intervals during the period 6 September-5 October 1980, at about 10 onshore stations and 3 offshore stations. The general flow pattern as- sociated with the mid-channel eddy (Fig. 2a) was observed to persist from 0100 to 0900 PDT; the Gaviota eddy (Fig. 2b) is clearly distinguishable on the 1100 and 1300 PDT maps. Be- tween 1500 and 1900 PDT the flow is primarily zonal, while the period from 2100 to 2300 PDT marks the development of the mid-channel eddy. The analyses of Smith et al. were limited by the lack of extensive observations offshore and through the boundary layer. However, the work is significant because it provided a preliminary conceptual model for understanding the importance of pollution sources and atmospheric transport within the SCCCAMP basin relative to advection of precursors and oxidants from adjacent regions. Bosart (1983) did an analysis of a four-day Catalina eddy event from May 1968, and established that the shallow low- level cyclonic circulation formed offshore of the Santa Barbara FIG. 2. Streamlines of most frequent September wind directions, coast and is due in part to topographic effects of the coastal after Smith et al. (1983). mountains. Once formed, the eddy was observed to expand seaward and southeastward beyond Los Angeles. Caldwell et radar), and a two-week period of intensive measurements that al. (1986) found considerable spatial and temporal mesoscale included hydrocarbon speciation, airborne remote sensing by wind variability during springtime (1983) in the western portion lidar, tetroon tracking, aerometric data from two aircraft, and of the Santa Barbara channel and coastal interior; two regions pilot-balloon-derived wind profiles at three locations. existed: an offshore region dominated by synoptic forcing, and The final design of the 1985 SCCCAMP continuous-moni- a coastal region influenced by the topography. And most re- toring network and intermittent-measurement facilities is doc- cently (prior to SCCCAMP), Blumenthal et al. (1986) described umented by Dabberdt et al. (1985), while the sampling criteria results of a limited experimental program of September 1983, and strategies for the intensive measurements are given by to document atmospheric transport from Los Angeles to Ventura Dabberdt and Viezee (1985). Detailed documentation of the County. Four transport mechanisms were observed, and in- operational aspects and meteorological conditions of the field cluded both coastal and interior and surface and elevated 4 measurements program is provided by Viezee and Dabberdt 'routes." (1987). In this review, we present descriptions of the mea- The organizational framework for SCCCAMP was estab- surement systems and the meteorological and chemical features lished in 1983 when a number of diverse groups formed an ad of the IOPs, and indicate the availability of the data base. hoc organization committed to a better understanding of the atmospheric physics and chemistry of the region for the explicit purpose of quantifying the impact of offshore petroleum activ- ities on photochemical oxidant levels. A formal memorandum 2. Experimental design and of agreement was subsequently adopted in 1985 by six gov- measurement systems ernmental agencies and one private organization: the regional office of the US Environmental Protection Agency, the Cali- The field measurement program was designed to provide me- fornia Air Resources Board, the Minerals Management Service teorological and air-chemistry data to initialize and evaluate of the US Department of Interior, the Air Pollution Control mesoscale models of boundary-layer dynamics and photochem- Districts of the counties of Santa Barbara, San Luis Obispo, istry. The data are also to be used in phenomenonological and Ventura, and the Western Oil and Gas Association. An analyses of atmospheric dynamics over the channel and some extensive two-year planning process included an objective eval- of the interior valleys and plains. The surface network consisted uation of meteorological and chemical modeling requirements of approximately 50 aerometric4 stations and 40 meteorological (Reynolds et al., 1985), the application of a mesoscale prim- stations; the latter included nine offshore platforms and buoys itive-equation meteorological model by Segal et al. (1985), and and the research vessel R/V Acania. Additionally, several an exploratory field measurements program during September hundred grab samples were collected on the ground and aloft, 1984 (Dabberdt, 1984). The latter was designed both to test and were analyzed for concentrations of trace species. Three measurement techniques and obtain limited meteorological and perfluorocarbon-gas tracers were released nearly coincidentally chemical data. The exploratory program consisted of a one- month period of continuous but limited measurements of sur- face winds and boundary-layer winds (by Doppler acoustic 4 Aerometric denotes both and air chemistry.

Unauthenticated | Downloaded 10/04/21 05:12 AM UTC 1100 Vol. 68, No. 9, September 1987 over four-h periods during each IOP, and 50 surface stations collected sequential two-h samples for up to two days after release. Dual X-band Doppler radars on a 46-km baseline pro- vided mean boundary-layer winds over the western half of the channel during IOPs. A network of eleven Doppler acoustic profilers and six rawinsonde sites provided upper-air data. IOP aircraft operations consisted of three aerometric aircraft, one meteorological aircraft, one dual-channel backscatter lidar, and one tracer-sampling aircraft. An operations center was estab- lished at the Ventura County Airport in Camarillo, and served as a data and forecast center, communications base, and staging area. IOP activities were scheduled and reviewed at briefings held daily at 1700 PDT. a. Surface-based observational program FIG. 3. Surface-based observational network. The surface-based observational network (Figure 3) included both existing, enhanced and new meteorological stations, aero- pressure and UV radiation on Platform Gina by EMSI; 7) wind, metric stations, rawinsonde sites, Doppler acoustic profilers temperature, pressure, and humidity observations provided by and microwave radars,5 and the R/V Acania. Existing onshore the American Peteroleum Institute at one oil platform (Hazel) surface meteorological measurements included 1) standard and from a operated from a boat; 8) wind mea- hourly weather observations from the National Weather Ser- surements by CARB from a 10-m tower on Anacapa Island; vice, Federal Aviation Administration, and the US Coast Guard and 9) micrometeorological observations by the NPS from the at 51 locations (including some outside of the primary R/V Acania. The shipboard observations included wind, tur- SCCCAMP region); 2) hourly observations of wind (mean and bulence, air temperature, and dew-point temperature at heights variance), temperature and temperature gradient from 15 oil- of 5 m and 20 m, as well as sea-surface temperature. These company stations and 14 stations maintained by the Air Pol- measurements were also used to estimate surface layer fluxes lution Control Districts (APCDs) of Santa Barbara and Ventura of momentum, heat and moisture using bulk parameterizations Counties; 3) eight US Forest Service stations in the Los Padres and the inertial dissipation method. The R/V Acania obtained National Forest which measure temperature, humidity and measurements during IOPs at a series of six positions from 3 wind; and 4) hourly observations of wind, temperature, and to 12 km south of the coastline between Goleta and Pt. Con- humidity at two mountain stations operated by the Pacific Mis- ception. Between IOPs, intercomparisons were made with buoy sile Test Center. Supplemental surface meteorological stations and platform observations in the Channel. The R/V Acania established onshore by SCCCAMP included 5) eight stations also served as a platform for release of perfluorocarbon tracers of the California Air Resources Board (CARB) that measured during three IOPs and for launches throughout the hourly 10-m winds; 6) eight remote portable remote observa- program (discussed later). tions of the environment (PROBE) stations provided by the Surface measurements of air chemistry included ozone Bureau of Reclamation to obtain 5-min observations of wind, (0 ), sulfur dioxide (S0 ), nitric oxide (NO), nitrogen dioxide temperature, pressure, and humidity, and operated by Envi- 3 2 (N0 ), total oxides of nitrogen (NO ), reactive organic com- ronmental Monitoring and Services, Inc. (EMSI); and 7) a 2 x pounds (ROC), total and speciated hydrocarbons, formal- 20-m mast of the Naval Postgraduate School (NPS) at the dehyde (HCHO), acetaldehyde (CH CHO), peroxyacetyl nitrate seaward end of the Ell wood pier near Goleta to measure 10- 3 (PAN), carbon monoxide (CO), chlorinated hydrocarbons, and min means and variances of the three-dimensional wind vector total suspended particulates (TSP). All variables were not mea- at one level, air temperature at two levels, and sea-surface sured at all existing or new stations. The existing air chemistry temperature. Offshore meteorological measurements were network consisted of approximately 34 stations, which typically made on buoys, oil platforms, four islands, and one research measure 0 , NO , S0 , TSP and total hydrocarbons, as well vessel. Existing measurements included 1) three NOAA Na- 3 x 2 as air temperature and wind speed and direction; these stations tional Data Buoy Office buoys (Point Conception, Point Sal, are operated by the two APCDs, the US Air Force, CARB, and Santa Monica); 2) wind and temperature measurements on and six oil companies (ARCO, Chevron, Exxon, Shell, Texaco two oil platforms (Grace and Hondo); and 3) three Automated and Unocal). Supplemental 0 measurements were made by Weather Observation Systems (AWOS) operated by the Pacific 3 EMSI at all nine PROBE locations and Platform Grace, while Missile Test Center on the islands of San Miguel, Santa Cruz, supplemental NO measurements were made at the PROBE site and San Nicolas. Supplemental SCCCAMP offshore surface x in Santa Paula. Other supplemental air chemistry measurements meteorological observations included 4) two buoys located in were made at six other onshore surface sites and one offshore the central and eastern portions of the Santa Barbara Channel site: EMSI measured 0 , NO , and ROC at Platform Gina and by Science Applications International Corp. (SAIC) to measure 3 x Laguna Peak, and ROC at Simi Valley. Environmental Re- hourly winds, pressure, UV radiation, and air and sea-surface search and Technology (ERT) measured PAN, HCHO and temperature; 5) wind measurements on oil Platform C provided CH CHO at Laguna Peak, Platform Gina and Simi Valley. PAN by AeroVironment, Inc. (AV); 6) wind, temperature, humidity, 3 measurements were obtained continuously at 15-min intervals by gas chromatography. Aldehyde samples were collected over 5 See Figure 11. three-h intervals in cartridges impregnated with two 4-dinitro-

Unauthenticated | Downloaded 10/04/21 05:12 AM UTC Bulletin American Meteorological Society 1101 phenylhydrazine and analyzed by high-pressure liquid chro- processed in this manner. Table 1 lists the operational periods matography with detection by UV absorption. Aldehyde and a priority ranking; all first-priority periods have been pro- samples were obtained at a frequency of one per day except cessed. The discussion of selected SCCCAMP observations during IOPs when diurnal sampling occurred on several days. (Section 4) includes two examples of radar data (Fig. 11); these Hydrocarbon and halocarbon speciation was performed by observations provide new insights into the structure and evo- Biospherics Research Corp. (BRC) on grab samples collected lution of the boundary-layer wind field over a large portion of at Platform Gina, El Rio, Ventura, Goleta, and Cuyama. A the Santa Barbara Channel. total of 92 thirty-minute samples were obtained twice daily in the early morning and midafternoon using evacuated 3.2-L stainless steel canisters overpressured to 5 psig during sam- b. Airborne observational program pling. The samples were analyzed later by gas chromatography Three twin-engine light aircraft (one Cessna 337 Skymaster and for CH4, CO, C2-C10 hydrocarbons and the halocarbons F = 12, F= 11, F= 113, CH3CCI3, CCI4, C HC1 and C C1 . two Piper Aztecs) were operated jointly by STI and AV to 2 3 2 4 measure both meteorological and chemical variables throughout Upper-air soundings of wind, temperature and humidity to the planetary boundary layer. Typically six missions were flown a minimum pressure altitude of 500 mb were obtained at four daily during the IOPs. Two aircraft each conducted flights in onshore and two offshore locations. Conventionally scheduled the early morning (takeoff about 0600 PDT), during the middle rawinsondes were available twice daily (0500 and 1700 PDT) of the day (1200 PDT takeoff), and during the early evening from Vandenburg Air Force Base (AFB). The Pacific Missile (takeoff near sunset, 1900-2000 PDT); each flight lasted up Test Center provided soundings two to four times daily, Mon- to three hours. The third aircraft functioned primarily as an day through Friday, at Point Mugu and San Nicolas Island alternate to ensure that two aircraft were always fully opera- (approx. 125-km due south of Carpinteria) as part of its regular tional for each flight period. The two aircraft simultaneously upper-air sounding program. Twice-daily rabal soundings (op- sampled different portions of the region; see Fig. 4, which tically tracked airsondes) at Loyola Marymount University in illustrates representative flight patterns of the so-called western Los Angeles were obtained by Metro Monitoring Services; the and eastern aerometric aircraft. The three aircraft were instru- 0600-PDT and 1200-PDT soundings were part of an operational mented virtually identically to sample (static) meteorological, air pollution program sponsored by the South Coast Air Quality air chemistry and navigational variables at a rate of 1 Hz; Table Management District and the CARB, respectively. Rawin- 2 summarizes the measured variables and the measurement sondes were obtained inland of the Santa Ynez Mountains at principles. A total of 63 flights spanning approximately 190 Cuyama Valley by Sonoma Technology, Inc. (STI); daily hours were made during the field program, and are summarized soundings were made midmornings except during IOPs when in Table 3. four soundings were obtained at 0500, 1030, 1600, and 2130 PDT. A similar schedule of soundings was followed by NPS Sampling patterns for each flight consisted of a series of aboard the R/V Acania at various locations in the Santa Barbara spirals and "dolphin" and constant-altitude traverses. During Channel. spirals, the aircraft ascended or descended at a rate of 150 m min-1 above a fixed reference location between the A network of 11 Doppler acoustic wind profilers provided surface and a typical maximum altitude of 1500 m(agl). Dol- continuous 30-60 min data to a nominal height of 600 m with phin traverses consisted of a succession of ascents and descents a vertical resolution of 30 m. Three profilers were operated between selected maximum or minimum altitudes. All traverses offshore by AeroVironment (AV) on San Miguel Island and were flown at air speeds of approximately 55 m • s 1(105 kt). Platforms C and Gina. AV also operated profilers at five on- The Research Aviation Facility of the National Center for shore locations: Point Dume, Santa Susana, Oak Flat, Man- Atmospheric Research (NCAR) operated its twin-engine dalay Beach (Oxnard), and La Cumbre Peak. Other onshore profiler locations included Point Mugu (PMTC), Goleta (NPS), and Gaviota (Westec Services for Texaco). Most of the profilers TABLE 1. Schedule of dual-Doppler radar observational periods. were at or near sea level, except four sites located in hilly or mountainous terrain: San Miguel I (130 m, msl), Santa Susana Date (1985) Period (PDT) Priority (550 m), Oak Flat (600 m), and La Cumbre (454 m). September 13 0430-0720 1 Additional boundary-layer wind data were obtained during 1330-1530 1 IOPs by dual-Doppler X-band radars from the Wave Propa- 14 0520-0810 2 gation Laboratory of the National Oceanic and Atmospheric 1210-1500 2 Administration. The radars were sited on the coast along a 46- 19 1330-1720 3 20 0450-0810 km baseline at Santa Barbara and Gaviota to obtain vertically 21 0630-1000 averaged two-dimensional wind measurements in the stable 1400-1730 marine boundary layer over a rectangular grid (33 km x 23 0830-1200 66 km). Because of the absence of adequate natural scatterers, 1850-2150 it was necessary to continuously release chaff during radar 24 0600-1000 1740-2140 operations. Two aircraft dispensed chaff at a constant altitude 25 0710-0940 of about 300 m; this limited the individual observational periods 1340-1620 2 to approximately four h. Synchronized low-elevation (<1.5°) October 2 0510-0835 3 radar scans were repeated every 5 or 10 min to produce hourly 1750-2145 1 3 0605-0955 1 composites of horizontal wind fields at overlapping intervals 2100-2355 1 of 30 min. Approximately 43 hours of gridded wind data were

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TABLE 2. Aircraft aerometric measurements.

Aircraft Type

Variables Aerometric Meteorological

Slow sampling: NO/NOx Chemiluminescence o3 Chemiluminescence bscat Integrating Grab samples Stainless steel canisters Visible radiation Pyranometer Ultraviolet radiation Photometer Photometer Infrared radiation Dissipation rate (e) Diff. pressure transducer Ambient temperature Bead thermistor Platinum resistance Dewpoint temperature Cooled mirror Cooled mirror Altitude Pressure transducer Radio altimeter Indicated airspeed Diff. pressure transducer Groundspeed / heading Inertial navigation system (INS) Position Loran-C INS Pitch/roll angles Inertial navigation resolver Radiometric sfc. temp. Bolometric radiometer Static/dynamic pressure Var. capacitance transducer

Fast sampling: Ozone NO chemiluminscence Humidity Lyman-a Microwave refractometer Ambient temperature Platinum resistance Three-component winds Gust probe and INS

Beechcraft Queen Air aircraft equipped with fast and slow The EPA Environmental Monitoring Systems Laboratory at meteorological , a fast ozone instrument, and an inertial Las Vegas (EMSL-LV) operated its dual-wavelength airborne- navigation system (INS). The Queen Air is denoted as the lidar system during all IOPs. The objectives of the lidar ob- SCCCAMP meteorological aircraft; Table 2 tabulates the ob- servational program were to obtain the three-dimensional served variables and instrument types. Mean and fluctuating aerosol distribution during morning and midday periods wind components were measured using the INS and a gust to document pollutant transport offshore and over the complex probe with fixed vanes mounted on the 2.7-m long-nose boom. inland topography. These observations provide both quantita- Other fast-response sensors included a boom-mounted plati- tive and qualitative information on the vertical structure of num-resistance , Lyman-a hygrometer, and mi- boundary layer and the effects of various topographic features crowave refractometer. Data from these fast sensors are on the transport wind field. sampled at 50 Hz and filtered at 20 Hz. Slow-response mea- surements included static and dynamic pressure, ambient and dewpoint temperatures, altitude, surface radiometric tempera- ture, and up welling and downwelling ultraviolet (UV), IR and visible radiation. These data are sampled at 5 Hz and filtered at 1 Hz. Colorado State University operated its Mark-I fast-response ozone analyzer. The instrument was originally described by Pearson and Stedman (1980) and uses the principle of chem- iluminescence of 03 with NO; it has a 3-dB bandwidth of 10 Hz and is calibrated over the range 0-300 ppbv. The morning sam- pling pattern (Fig. 4a) zig-zagged over the Santa Barbara Chan- nel within the MBL to obtain thermodynamic and kinematic data on the structure of the land-breeze-circulation offshore of the Oxnard Plain and the drainage flows along the coastline offshore of the Santa Ynez Mountains, and provide in situ wind measurements to complement and evaluate the radar-derived MBL wind fields. The midday flights (Fig. 4c) were configured to evaluate turbulent and advective ozone fluxes offshore and inland through the Santa Clara River Valley and the Oxnard Plain. In addition to these two basic flight patterns, several deep soundings were obtained to about 4200 m(msl) at Ca- marillo Airport. Table 3 also summarizes the flight activity for FIG. 4. Representative flight patterns for aerometric and meteoro- the Queen Air. logical aircraft.

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TABLE 3. Aircraft flight summary.

Aircraft "Type"

Aerometric (east) Meteorological Lidar Tracer Aerometric (west) (PDT) (PDT) (PDT) (PDT)

Date (1985) September 12 1951-2223 1933-2117 13 0532-0808 0533-0759 0611-0857 0720-1000 1225-1458 1228-1502 1340-1640 1053-1227 1928-2105 1930-2037 1705-2030 14 0555-0733 0557-0709 0615-0830 1227-1628 1230-1505 1907-1957 1335-1655 1154-1404 19 1225-1436 1055-1213 0533-0802 0555-0827 0557-0843 0600-0830 0926-1300 20 1159-1432 1205-1438 1319-1525 1230-1530 1922-2102 1926-2030 1708-2010 0623-0852 0628-0856 0609-0859 0605-0840 0729-0959 21 1203-1345 1204-1317 1216-1300 1240-1530 1923-2121 1930-2039 1156-1430 1201-1432 1156-1320 22 1924-2125 1927-2036 23 0558-0833 0601-0832 0610-0900 1208-1447 1225-1455 1200-1320 1230-1530 1947-2223 1934-2135 2014-2054 24 0659-0832 0601-0832 0610-0840 0847-1225 1210-1455 1157-1422 1220-1500 1858-2144 1848-2030 (1851-2115)* 1536-1854 25 0605-0853 0606-0824 0650-1114 1208-1451 1209-1514 27 1654-1758

October 1 1928-2158 1855-2108 2 0600-0829 0602-0915 0605-0905 1200-1543 1158-1434 1200-1313 1858-2121 1846-2050 0600-0834 0603-0839 0557-0843 0600-0845 0703-1133 1202-1440 1208-1440 1202-1418 1230-1520 1847-2049 (1536-1617)* 1558-1917 1058-1147 1033-1308 1055-1355

* Special supplemental flight by third aerometric aircraft. and the NOAA Air Resources Laboratory. Tracer tests were The lidar system uses a neodymium-YAG laser and a fre- undertaken during each of the four IOPs with the objective of quency doubler to simultaneously transmit 17-ns pulses in the characterizing multiday mesoscale transport and recirculation green (0.532 |xm) and infrared (1.064 jjim) at a total power within the SCCCAMP region. The three inert tracers used and of 125 mJ. The nominal 2s 1 pulse repetition rate and their tropospheric background concentrations are perfluoro- 123 m • s-1 maximum air speed of the twin-engine Aerocom- methylcyclopentane (PMCP or PPi; 3 x 10"3 ppt); perfluo- mander provide a minimum horizontal resolution of 62 m. romethylclohexane (PMCH or PP2; 4 X 10 3 ppt); and The vertical resolution is 6 m and extends from the ground perfluorodimethylcyclohexane (PDCH or PP3; 3 x 10"2 ppt). surface to about 150-m below the flight altitude (typically Each test consisted of a 4-h release of the three tracers at two 3000 m[msl]). A total of 16 flights was made on 9 separate or three locations; some tests released two different PFTs se- days; the duration of each flight varied from 135 to 180 min quentially from the same location. Release points included three (see Table 3). The early morning flight pattern concentrated offshore surface locations (R/V Acania, about 24 km off Pt. on the coastal sectors and included traverses across the eastern Conception; Platform Hondo, about 40 km west of Santa Bar- end of the Santa Barbara Channel, through the Oxnard Plain bara; and Platform C, about 11-km south-southeast of Santa inland to Santa Susana, inland near the coast from Camarillo Barbara), one surface coastal location (Mandalay Beach, mid- to Santa Barbara and on to the Santa Ynez Valley, and across way between Ventura and Point Mugu); and one elevated in- the Channel from Gaviota to San Miguel Island and obliquely terior location (18-km north-south track, 760-m altitude, just back to Ventura. The midday flight pattern was more extensive east of Van Nuys Airport) in the San Fernando Valley. The and covered more of the interior portions of the region as well times, locations, and release rates are summarized in Table 4, as repeating much of the overwater tracks of the morning flight. while Fig. 5 illustrates the location of the releases and the location and type of the ground-level sampling devices. c. Gas tracer studies Tracer concentrations were measured by two types of sam- Perfluorocarbon gas tracer (PFT) experiments were conducted pling systems: one for airborne sampling and the other for jointly by SRI International, Pacific Northwest Laboratories, surface sampling. Airborne PFT measurements used a two-trap

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air and served as a quality-control sample to evaluate contam- ination; 2) Fourteen sites employed programmable NO A A Se- quential Atmospheric Tracer Samplers (SATS) each of which obtained 12 sequential two-h samples; and 3) Twenty-five BATS sites also employed Totalizing Atmosphere Tracer Sam- pler (TATS) samplers each of which collected two sequential 24-h samples that provided a balance check for the colocated BATS samplers. Tracer sampling was initiated at 0200 PDT on September 13, 20, and 24, while on 2 October, the BATS samplers were activated at 1400 PDT and the NO A A samplers at 2000 PDT. Laboratory analysis of the PFT samples followed the analytical technique developed by Dietz and Senum (1984). After thermal desorbtion from the Ambersorb tubes, the sample was passed over a palladium (Pd) catalyst bed at 170°C, through FIG. 5. Tracer release and sampling locations. a precolumn at 140°C and reconcentrated on a Porapak QS trap at ambient temperature. The trap was flash heated to 200°C and the sample injected into a Varian Vista 6000 gas chro- chromatographic sampler to obtain realtime five-min data from matograph where it passed over a second Pd bed, through a a Cessna 402 twin-engine aircraft. The sampler contains dual permeation dryer and into the main column; PFT analysis was carbonaceous (Ambersorb) traps which sequentially collect with an electron capture detector. System calibration used three -1 sample air at 0.5 L • min ; while one trap is sampling, the high-purity standard mixtures, which each contained all three other is desorbed and its sample is passed through two columns PFTs at concentrations of 10°, 102, and 104 ppt in ultra pure and analyzed with an electron-capture detector. Eleven flights, nitrogen. each of 3-4 h duration, were conducted. The first flight of each IOP was designed for the morning immediately following tracer release and emphasized mapping tracer distribution over the channel, the Santa Clara and Ojai Valleys, and the Oxnard 3. IOP characterization Plain. The second flight occurred during the late afternoon of the same day and sampled the eastern channel as well as the Previous studies in the SCCCAMP region have identified three same inland areas as the earlier flight. The third flight of each broad types of meteorological regimes under which offshore IOP nominally took place on the following morning, and used emissions of nitrogen oxides and hydorcarbons may contribute a pattern similar to the first morning flight. Flight altitudes in varying degrees to onshore photochemical-oxidant concen- ranged from 75 to 900 m(msl) with the earlier flights usually trations. The first regime is associated with a moderate-to- at lower levels. strong onshore pressure gradient that transports offshore emis- A fixed network of 50 surface stations (Fig. 5) collected sions inland in accordance with the synoptic-flow field. Local tracer material on adsorbent traps over periods ranging up to land-sea-breeze and mountain-valley circulations modify the 48 h; samples were analyzed after the experiment in SRI In- synoptic flow and can prolong the residence time of pollutants ternational's analytical PFT laboratory. Three types of sampling within the airshed. The relative contribution of offshore emis- devices were deployed in the network: 1) Thirty-six sites sions may be high under this regime although oxidant concen- employed programmable Brookhaven Atmospheric Tracer trations are not expected to be high in an absolute sense. With Samplers (BATS), which each collected 22 sequential 2-h an offshore pressure gradient—the second regime, local cir- samples while one additional sample was not exposed to ambient culations further increase the residence time and can result in higher oxidant concentrations. While the absolute contribution of offshore emissions may be the same or greater than the first TABLE 4. Summary of tracer releases. regime, the contribution of precursors and oxidants from out- Rate side the South Central Coast Air Basin (SCCAB) is expected Date Location* Time (PDT) Tracer (kg h-1) to be larger due to inland transport from Los Angeles and the South Coast Air Basin. In the third regime, general air-mass September 13 R/V Acania 0400-0800 PMCH 2.9 stagnation occurs and the local circulations dominate the trans- Platform Hondo 0200-0600 PMCP 2.0 port patterns. This regime is often accompanied by light noc- Platform Hondo 0600-1000 PDCH 7.0 September 20 R/V Acania 0400-0800 PDCH 8.75** turnal flow along the coast from Santa Monica Bay. Peak Platform Hondo 0300-0700 PMCP 2.0 SCCAB oxidant concentrations frequently are attributable to Mandalay 0100-0500 PMCH 2.9 this regime. In the following discussion, the meteorological September 24 R/V Acania 0402-0810 PDCH 6.6 conditions during SCCCAMP are reviewed with particular em- Platform Hondo 0300-0700 PMCP 2.0 San Fernando 0315-0615 PMCH 3.0 phasis on conditions during IOPs: 1) 13-14 September; 2) 20- Valley 21 September; 3) 23-25 September; and 4) 2-4 October. October 2 Platform C 1634-2106 PDCH var. The daily variation of mixing depth derived from the Van- Platform Hondo 0300-0700 PMCP 2.0 denburg RAOBs is plotted in Fig. 6 along with the ambient Mandalay 1600-2000 PMCH 3.0 temperature at 850 mb. Here the mixing depth is defined as the * See Figure 5. height of the base of the lowest temperature inversion. The ** Hourly rates: 4.6, 5.7, 10.9 and 13.8 kg h"1. combination of shallow mixing depth and elevated 850-mb

Unauthenticated | Downloaded 10/04/21 05:12 AM UTC Bulletin American Meteorological Society 1105 temperature is a prerequisite for high surface concentrations. rapid warming at 850-mb, and shallow mixing depths. Warm- The four IOPs are seen to coincide with periods where this air advection toward the west coast occurred on the south side combination prevails. Figure 6 also shows the daily variation of the surface high. Surface ozone concentrations on 13 Sep- of the 1000-PDT wind direction at Laguna Peak, which is tember in the interior portions of Ventura County were in excess located on the coast adjacent to Point Mugu (on the eastern of the federal 120-ppb primary standard. Following the first border of the Oxnard Plain—see Fig. 1). Laguna Peak rises IOP, another cold low persisted for several days, dropping 850- abruptly above the coastline to an elevation of 450 m and is mb temperatures 10°C below normal and destroying the sub- particularly representative of the synoptic flow when the mixing sidence inversion. depth is low. Only during the first, third, and fourth IOP does The second and third IOPs were characterized in central and the Laguna Peak wind direction have an easterly component. southern California by a pressure col at 500 mb with a strong (The second IOP was, in fact, selected because the shallow- low-pressure trough to the NE, low pressure to the SW, and mixing depth and NW flow provided an opportunity to obtain high pressure to the NW and SE. Upper-level winds were data with which to model potential oxidant impacts of planned relatively weak and the sea-level pressure gradient was pre- oil developments offshore of the Point Conception-Vandenburg dominantly offshore. Temperatures at 850 mb increased to coastline when emissions from this area would be transported 20°C and strong subsidence decreased the mixing depth to less to coastal Santa Barbara and Ventura Counties). than 300 m. As indicated earlier, surface ozone concentrations Figure 7 presents time series of daily peak-hour ozone con- in the SCCAB during the second IOP were within the federal centration at Santa Barbara, Ventura, Ojai, and Simi. During standard. However, the third IOP was accompanied by high the first IOP, the 120-ppb federal ozone primary standard was ozone concentrations along the central and eastern Santa Bar- exceeded in the interior portions of Ventura County as indicated bara County coastline and in the interior Ventura County valleys by measurements at Ojai (140 ppb) and Simi (170 ppb). High on 24 September, and were generally a factor of two higher ozone concentrations were not observed at any of the stations than on either the preceding or following day. To the west of during the second IOP; in fact, none were forecast as discussed Santa Barbara, ozone extremes were observed at Goleta previously. The third IOP is especially noteworthy because of (230 ppb) and El Capitan (200 ppb). record ozone levels (230 ppb) at Goleta in coastal Santa Barbara The fourth IOP was characterized by an upper-level ridge of County. In Ventura County, ozone at the interior Ojai (190 high pressure extending into California from the northwest. ppb) and Simi (180 ppb) stations was significantly lower but During this period, a strong offshore sea-level-pressure gra- still excessive. Equally important in the understanding of this dient developed and the 850-mb temperature reached its max- episode is the low 100-ppb maximum observed at the coastal imum value of 22°C for the SCCCAMP field period. However, Ventura site. The fourth IOP was characterized by high coastal daytime surface heating destroyed the elevated inversion inland concentrations at Ventura (170 ppb) and Goleta (130 ppb), and and vented pollution out of the boundary layer. As a conse- very low levels (60 and 90 ppb) at the two interior locations. quence, surface ozone concentrations peaked along the coast During the period 3-11 September, meteorological condi- and offshore regions, and decreased rapidly inland; the coastal tions in the area were dominated by an anomalous succession ozone maximum on 3 October at Ventura was 190 ppb while of cold low-pressure systems that moved into southern Cali- Ojai (90 ppb) and Simi (60 ppb) typified the lower interior fornia out of the Gulf of Alaska. Sea-level-pressure gradients concentrations. in the SCCCAMP region were predominantly onshore, 850- In summary, weather conditions throughout the period of the mb temperatures were more than 8°C below the normal of 18°C, field study were characterized by rapid and pronounced syn- and mixing depths increased to 2 x 103 m and more. During the period 12-16 September, a subtropical high-pressure system centered over Texas extended into southern California accom- panied by subsidence, offshore sea-level-pressure gradient,

FIG. 6. Daily variation of mixing depth and 850-mb temperature at Vandenburg and morning wind direction at Laguna Peak (450 m msl); shading indicates periods with easterly wind component and IOP sec- FIG. 7. Daily variation of maximum hourly surface ozone concen- tors. tration.

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FIG. 9. Vandenburg soundings for 23-24 September.

FIG. 8. 500-mb map for 0500 PDT, 24 September. optic-scale changes. Although meteorological conditions fa- vorable for development of excessive ozone concentrations did occur, they did not persist for more than two or three successive days.

4. Selected observations

The third IOP (23-25 September) has been selected here to FIG. 10. Preliminary surface streamline analyses for 24 September exemplify the data from several of the aperiodic measurement a) 1100 PDT and b) 1500 PDT. systems and to provide a few examples of the atmospheric structure that resulted in record oxidant concentrations in coastal Santa Barbara County and significant concentrations in mb level. Preliminary surface-streamline analyses were pre- interior Ventura County. The general synoptic pattern in the pared in real time throughout the IOP; Fig. 10 shows updated Pacific southwest states was strongly influenced by a tropical analyses for 1100 and 1500 PDT on 24 September. Clearly disturbance, which at 1200 UTC on 24 September was centered indicated are the significant temporal and spatial variations in at about 28°N/132°W; at the surface the disturbance was off the surface wind field on this day. In the morning the flow in the coast of Baja California, centered about 28°N/120°W. The northwest quadrant is NW and suggests the formation of a east-southeast flow on the east side advected warm air into Gaviota eddy, while in the southeast quadrant the flow is east- southern California, resulting in a very strong low-level in- erly and turns anticyclonically from the channel into the Oxnard version (15.5°C) that is reflected in the Vandenburg soundings Plain. A north-south convergence line is present at the eastern (Fig. 9). At 0500 PDT, the highest temperature in the inversion portion of the Oxnard Plain and an east-west convergence zone was about 26°C at 920 mb and represented a warming of nearly is suggested through the central portion of the channel. By mid- 4°C over the previous 12 h. The wind profile at 1700 PDT on afternoon, the inland convergence zone has moved further east 23 September, indicates significant backing to 750 mb and light although the flow is light yet well organized. Similarly the variable winds above. On 24 September, both the 0500 and winds in the channel are light. The wind fields derived from 1700 PDT profiles indicate strong SE flow through the 500- the dual-Doppler radar observations are particularly valuable

Unauthenticated | Downloaded 10/04/21 05:12 AM UTC Bulletin American Meteorological Society 1107 under these conditions. In the early morning (0730 PDT), Fig. data at these two sites reflect not only their geographic ori- 11 shows a weak cyclonic mid-channel eddy present over the entation with respect to the locations of the tracer releases, but west-central channel; speeds range from near calm up to about also the blocking effect of the Santa Ynez Mountains. At Jalama 4 m • s"1 and the average velocity within the entire radar grid Beach the PMCP concentration first increases rapidly with the is 070° at 1.14 m • s"1. The late-afternoon wind field at 1810 1000-1200 PDT sample (six h after the middle of the four-h PDT does not indicate a closed circulation as was seen that release from Platform Hondo), peaks between 1200 and 2000 morning. The mean flow continues to have a pronounced east- PDT, and remains elevated through the 0000-0200 sample of erly component (2.80 m • s"1 at 097°) with a significant sinu- 25 September—a period of elevated concentrations of about soidal pattern superimposed; the wavelength is 42 km and the 16 h. Neither of the tracers released from the R/V Acania amplitude, 17 km. (PDCH) and above Van Nuys (PMCH) was detected at Jalama Time series of two-h tracer concentrations at Jalama Beach Beach. At the Santa Ynez sampling site, a large PMCH peak and Santa Ynez are illustrated in Fig. 12. The Jalama Beach (200 fL • L _1 or 35 times the measured background) is ob- site (Fig. 1) is on the coast approximately 10-km northwest of served from 1200 to 1600 PDT on the same day as the 0315- Point Conception while Santa Ynez is at an elevation of 200 m 0615 PDT aircraft release at 760 m above Van Nuys; a sec- in the Santa Ynez Valley, about 40-km west-northwest of Santa ondary PMCH peak is observed to begin about six h later at Barbara; the Santa Ynez Mountains form a ridge 900-1300-m Santa Ynez. The time between release and the primary peak- high, which runs east-west along the coast and separates the yields a transport velocity of about 4.5 m • s~\ which is con- Santa Ynez Valley from the Santa Barbara Channel. The tracer sistent with the Vandenburg upper-level winds. The Santa Ynez tracer measurements also indicate a broad PMCP (Hondo) peak that extends from about 1800 PDT on 24 September through 0800 PDT on 25 September. The PDCH data are less definitive although they suggest tracer released from the Acania may have been detected on 25 September; two small peaks are present around 0700 and 1900 PDT. Airborne-lidar observations on the afternoon of 24 September were made from 1220 to 1500 PDT. Figure 13 is an intensity modulated (gray scale) vertical cross-section obtained with the green channel during the middle portion of that flight along a 125-km leg that originated in Santa Monica Bay and extended along a northwesterly heading to the Santa Ynez Mountains. Surface winds over Santa Monica Bay were SSW while between

FIG. 11. Two-dimensional gridded hourly MBL wind fields derived from dual-Doppler radar measurements (from Kropfli, 1986) a) 0730 FIG. 12. PFT tracer time series at Jalama Beach and Santa Ynez PDT and b) 1810 PDT. (from Endlich, 1987).

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a depth of about 400 m(agl). Corresponding surface ozone con- centrations in this region varied from about 150 to 175 ppb. At this time the surface winds along this portion of the flight leg were WSW (approximately normal to the flight track) be- cause of the intrusion of the sea breeze; however, the land breeze had persisted through 1000 PDT and the source of the particulates may have been the Simi and San Fernando Valleys. Early afternoon aircraft profiles of ozone and temperature at Platform Gina, Santa Paula, and Ojai are plotted in Fig. 14. The temperature profile at 1306 PDT above Platform Gina (about 17-km due south of Ventura) shows a surface-based inversion of 7.5°C that extends to a height of about 700 m; embedded within the inversion is a sharp peak of 290 ppb in the ozone profile. Santa Paula (in the Santa Clara Valley and FIG. 13. Airborne lidar cross section during early afternoon of 24 about 22-km inland of the Ventura coastline) was downwind September (from McElroy, 1987). of Platform Gina on the afternoon of 24 September, and its temperature profile indicates warming at all levels in compar- ison with boundary-layer conditions over the channel; a weak Thousand Oaks and Santa Paula, surface winds were WSW; surface-based inversion of 1.5°C extends to about 300 m(agl). above the boundary layer, the flow was SSE. The data reso- The corresponding 03 profile has a maximum of 240 ppb at lution of the video display shown in Fig. 13 is only four bits the minimum aircraft altitude of 75 m(agl), and remains more or 16 shades of gray; resolution of the digital data record is or less constant around 200 ppb between 250 and 750 m(agl); eight bits. The earth surface is depicted by the upper boundary above 750 m, the 03 concentration decreases sharply to of the white area in the illustration. The stable stratification of 130 ppb at 900 m(msl). The Ojai Valley profile was obtained the MBL is apparent from the horizontal strata over Santa about one-hour later about 18-km northwest of Santa Paula. Monica Bay, which persist inland above the Santa Monica Again the maximum 03 concentration of 280 ppb was measured Mountains. Further inland, convective mixing is observed to a at the minimum aircraft altitude of 50 m(agl), and decreased height of about 2-km(msl) and aerosol concentrations near rather monotonically to 130 ppb at the top of the spiral at the surface are decreased accordingly. About this same time, 1300 m • agl. These aircraft observations provide further doc- coastal ozone concentrations near Malibu Beach were about umentation of the widespread distribution of the extremely high 90 ppb while at Thousand Oaks concentrations were about ozone levels during this episode, and, when coupled with the 175 ppb. Across the interior portions of the Oxnard Plain (i.e. other airborne and surface aerometric and tracer measurements, the Santa Rose Valley), the Santa Clara Valley and the Ojai will help to better understand the mechanisms contributing to Valley, aerosol loadings near the surface increase again through such events and the relative importance of local versus extra- mural emission sources in the SCCAB.

5. Data availability

The SCCCAMP meteorological and air chemistry data are being edited and archived by SRI International under the direction of Roy M. Endlich. A composite archive of data from all mobile and stationary measurement platforms (except the airborne li- dar) is scheduled to be completed July 1987; inquiries regarding data availability and format should be addressed to: US De- partment of the Interior, Minerals Management Service, (Pa- cific OCS office), 1340 West Sixth Street, Los Angeles, CA 90017, Attention: Mr. Tom Chico. Inquiries concerning the availability of the lidar data should be forwarded to: US En- vironmental Protection Agency, Environmental Monitoring Systems Laboratory, Post Office Box 15027, Las Vegas, NV 89114, Attention: Dr. James McElroy.

Acknowledgments. The authors gladly acknowledge the contributions by Ms. Mary Ann Pykkonen for "typesetting" the manuscript and Mr. Lee Fortier, Ms. Barb Mericle, and Ms. Gaylynn Potemkin for drafting the illustrations. The first author was the SCCCAMP Technical Director FIG. 14. Aircraft ozone and temperature profiles during the early while at SRI International and joined NCAR on conclusion of the field afternoon of 24 September (adapted from Anderson et al., 1986). measurement program. The authors also wish to acknowledge the sig-

Unauthenticated | Downloaded 10/04/21 05:12 AM UTC Bulletin American Meteorological Society 1109 nificant technical contributions and support of the SCCCAMP Tech- Appendix B Cooperative organizations nical and Scientific Advisory Committees, and particularly the leadership of Dr. Steve Ziman. The SCCCAMP field measurement American Petroleum Institute, Washington, DC program was jointly sponsored by the Western Oil and Gas Association, US Environmental Protection Agency, Minerals Management Service, Atlantic Richfield Company, Los Angeles, California and California Air Resources Board. Chevron USA, Inc., San Ramon, California Exxon Company USA, Thousand Oaks, California Pacific Missile Test Center, Pt. Mugu, California Phillips Petroleum Company, Denver, Colorado Appendix A Participating organizations and Santa Barbara County Air Pollution Control District, Santa principal scientists Barbara, California Shell Oil Company, Carson, California Mr. George Ettenheim AeroVironment, Inc., Southern California Edison Company, Rosemead, California Mr. Robert Baxter Monrovia, California Texaco Inc., Universal City, California Dr. Rei Rasmussen Biospherics Research Corp., Unocal Corporation, Los Angeles, California Hillsboro, Oregon U.S. Air Force, Vandenburg, California Mr. Andy Ranzieri California Air Resources U.S. Forest Service, Boise, Idaho Board, Sacramento, Ventura County Air Pollution Control District, Ventura, Cal- California ifornia Dr. Richard Pearson Colorado State University, WSI Corporation, Bedford, Massachusetts Fort Collins, Colorado Dr. Miriam Lev-On Environmental Monitoring and Services, Inc., References Newbury Park, California Dr. Kochy Fung ERT, Inc., Newbury Park, Anderson, J. A., D. Blumenthal, D. E. Lehrman, J. A. McDonald, California R. A. Baxter, K. Field, K. Bumiller, and W. C. Brick, 1986: Dr. Peter Hildebrand National Center for SCCCAMP aerometric aircraft program summary and data presen- Atmospheric Research, tation, Final Report, Sonoma Technology, Inc., Santa Rosa, CA Boulder, Colorado 95401, 27 pp. National Oceanic and Atmos. Baynton, H. W., J. M. Bidwell, and D. W. Beran, 1965: The asso- Mr. Ray Dickson Administration, Air ciation of low-level inversions with surface wind and temperature Resources Laboratory, at Point Arguello, J. Appl. Meteor., 4, 509-516. Idaho Falls, Idaho Blumenthal, D. L., T. B. Smith, D. E. Lehrman, N. L. Alexander, National Oceanic and Atmos. F. Lurmann, and D. Godden, 1986: Analysis of aerometric and Mr. Robert Kropfli Administration, Wave meteorological data for the Ventura County region, Final Report STI 90094-511-FR, to Western Oil and Gas Association, by Sonoma Propagation Laboratory, Technology, Inc., Santa Rosa, CA 95401, 182 pp. Boulder, Colorado Bosart, L. F., 1983: Analysis of a California Catalina eddy event, Mon. Dr. Will Shaw Naval Postgraduate School, Wea. Rev., Ill, 1619-1633. Dr. Charles Skupniewicz Monterey, California Caldwell, P. C., D. W. Stuart and K. H. Brink, 1986: Mesoscale wind Dr. William Pennell Pacific Northwest variability near Point Conception, California during spring 1983, J. Laboratories, Richland, Clim. Appl. Meteor., 25, 1241-1254. Washington Dabberdt, W. F., 1984: Activity summary for the 1984 South Central Dr. Gil Stegen Science Applications Coast Cooperative Aerometric Monitoring Program (SCCCAMP) International Corp., exploratory study, Technical Report to Western Oil and Gas Asso- ciation, by SRI International, Menlo Park, CA 94025, 22 pp. Bellevue, Washington Dabberdt, W. F., W. Viezee and K. C. Nitz, 1985: SCCCAMP field Dr. Don Blumenthal Sonoma Technology, Inc., study design, Vol. I—monitoring network, Technical Report 8331 Mr. Jerry Anderson \ Santa Rosa, California to Western Oil and Gas Association, by SRI International, Menlo Mr. William Knuth J Park, CA 94025, 85 pp. Dr. Walter Dabberdt*' Dabberdt, W. F., and W. Viezee, 1985: SCCCAMP field study design, Mr. William Viezee SRI International, Menlo Vol. II—sampling criteria and strategies, Technical Report 8331 to Dr. Warren Johnson* Park, California Western Oil and Gas Association, by SRI International, Menlo Park, Mr. Roy Endlich CA 94025, 52 pp. Dr. James McElroy US Environmental Protection Dietz, R. N., and G. I. Senum, 1984: Capabilities, needs and appli- Agency, Environmental cations of gaseous tracers, Atmospheric Tracer Workshop, LA- 10301-C, Los Alamos National Laboratory, Los Alamos, NM, 123- Monitoring Systems 173. Laboratory, Las Vegas, Edinger, J. G., 1963: Modification of the marine layer over coastal Nevada southern California, J. Appl. Meteor., 2, 706-712. Edinger, J. G., and M. Wurtele, 1971: Marine layer over sea test range, Pacific Missile Range Publ. TP-71-2, Pt. Mugu, California, 93024, 95 pp. Endlich, Roy M., 1987: personal communication, SRI International, : present affiliation, NCAR Menlo Park, CA 94025.

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Giroux, H. D., L. E. Hansen and L. Teuscher, 1974: Power plant Joint Conf. Applic. of Air Poll. Meteor., Salt Lake City, 12-15. plume tracing in the southern California marine layer, from Proc. McElroy, J. M., 1987: personal communication, U.S. Environmental Symp. Atmos. Diff. and Air Poll., 9-13 Sept. 1974, Santa Barbara, Protection Agency, Environmental Monitoring Systems Laboratory, CA, 238-245, Amer. Meteor. Soc., Boston, MA. Las Vegas, NV 89114. Hay den, P., F. Lurmann, D. Godden and B. Nitta, 1981: Atmospheric Pearson, R. D. H. and D. H. Stedman, 1980: Instrumentation for fast vertical temperature structure and inversion heights for Santa Barbara response ozone measurements from aircraft, Atmos. Tech., 12, 51- and Ventura Counties, Report No. P-A715-300, prepared for Western 55. (National Center for Atmospheric Research, Boulder, CO). Oil and Gas Association, by Environmental Research and Technol- Reynolds, S. D., T. W. Tesche, D. R. Souten and M. K. Liu, 1985: ogy, Inc., Newbury Park, CA, 11 pp. Overall study protocol for the South Central Coast Cooperative Aero- Kauper, E., and B. L. Niemann, 1975: Los Angeles to Ventura metric Monitoring Program, Final Report to Western Oil and Gas overwater ozone transport study, Final Report to California Air Association, by Systems Applications, Inc., San Rafael, CA 94903. Resources Board, Metro Monitoring Services, Covina, CA 91723, Schacher, G. et al., 1982: California coastal offshore transport and 75 pp. diffusion experiments-meteorological conditions and data, Report Kropfli, R. A., 1986: Summary of dual-Doppler radar observations NPS-61-82-007 to Bureau of Land Management, Department of during SCCCAMP, Tech. Mem. ERL WPL-141, National Oceanic Interior, by Naval Postgraduate School, Monterey, CA 93943, 377 and Atmospheric Administration, Environmental Research Labora- pp. tories, Wave Propagation Laboratory, Boulder, Colo., 97 pp. Segal, M., R. T. McNider and R. A. Pielke, 1985: Use of a mesoscale Lamb, B. K., A. Lorenzen and F. H. Shair, 1978: Atmospheric dis- primitive equation model in the design of the 1985 SCCCAMP, Final persion and transport within coastal regions—Part I. Tracer study Report to Western Oil and Gas Association, by ASTeR, Inc., Ft. of power plant emissions from the Oxnard Plain, Atmos. Environ., Collins, CO 80522, 76 pp. 12, 2089-2100. Smith, T. B., W. D. Saunders and F. H. Shair, 1983: Analysis of Santa Lea, D. A., 1968: Vertical ozone distribution in the lower troposphere Barbara oxidant study, Final Report to California Air Resources near an urban pollution complex, J. Appl. Meteor., 7, 252-267. Board, Agreement A2-086-32, by Meteorology Research, Inc., Lee, T. F., 1979: Diurnal variations of coastal stratus, Publ. TP-80- Altadena, CA 91001, 236 pp. 02, Pacific Missile Test Center, Pt. Mugu, CA 93042, 59 pp. Viezee, W. and W. F. Dabberdt, 1987: Documentation of the Lehrman, D., T. B. Smith, D. Reible and F. Shair, 1980: A study of SCCCAMP'85 field study, Final Report 8331 to South Central Coast transport into, within and out of coastal areas of southern Santa Cooperative Aerometric Monitoring Program, by SRI International, Barbara County and Ventura County , Final Report MRI81 FR-1808, Menlo Park, CA 94025, 132 pp (February). to Ventura Air Pollution Control District by Meteorology Research, Zannetti, P., D. Wilbur and R. Baxter, 1981: Southern California Inc., Altadena, CA 91001, 100 pp. offshore air quality model validation study, Final Report to Bureau Maas, S. and P. Harrison, 1977: Dispersion over water, a case study of Land Management, Department of Interior, by AeroVironment, of a non-buoyant plume in the Santa Barbara Channel, from Proc. Inc., Monrovia, CA 91016-3424, 150 pp. •

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