SPECIAL SCIENTIFIC REPORT-FISHERIES Na406

:406

OCEANOGRAPHIC OBSERVATIONS, 1960, EAST COAST OF THE UNITED STATES

WOODS HOLE, MASS,

SPECIAL SCIENTIFIC REPORT-FISHERIES Na406

UNITED STATES DEPARTMENT^FJ^i^^ pisiTANinwILDUFnERvi^ This work was financed by the Bureau of Connmercial Fisheries

under Contract No. 14-17-0007-9, with funds made available under

the Act of July 1, 1954 (68 Stat. 376), commonly known as the Saltonstall-

Kennedy Act. UNITED STATES DEPARTMENT OF THE INTERIOR, Stewart L. Udall, Secretary FISH AND WILDLIFE SERVICE, Clarence F. Pautzke, Commissioner Bureau of Commercial Fisheries, Donald L. McKeman, Director

OCEANOGRAPHIC OBSERVATIONS, 1960 EAST COAST OF THE UNITED STATES

C. Godfrey Day Research Associate Woods Hole Oceanographic Institution Woods Hole, Massachusetts

Contribution No. 1202 from the Woods Hole Oceanographic Institution

United States Fish and Wildlife Service Special Scientific Report--Fisheries No. 406

Washington, D. C. 1963 Frontispiece. Locations along the Atlantic Coast reported herein. .

CONTENTS Page

Introduction 1 Commentary 1 Summary for 1956-60 1 Surface temperature 1 The the rmoc line 3 Bottom water temperature 3 Salinity 3 Meteorological effects 3 The 1960 data: Surface temperature 4 Bottom temperature 4 Mt. Desert Rock Light Station 5 Portland Lights hip 7 Boston Lightship 11 Georges Shoal, Texas Tower §Z 15 Nantucket Shoals, Texas Tower #3 17 Nantucket Lightship 18 Woods Hole, Massachusetts 22 Buzzards Lightship 2 3 Kingston, Rhode Island 25 Ambrose Lightship 26 Texas Tower #4 (off New York) 30 Barnegat Lightship 31 Five Fathom Bank Lightship 35 Winter Quarter Lightship 39 Chesapeake Lightship 43 Diamond Shoals Lightship 47 Frying Pan Shoals Lightship 51 Savannah Lights hip 55

Literature cited - 59 FIGURES

Frontispiece. Locations along the Atlantic coast reported herein 1. Normal cycle of temperature at surface and bottom along the string of observation posts for I960 4 2. Mt. Desert Rock Light Station 5 3. Portland Lightship 7 4. Boston Lightship 11 5. Georges Shoal, Texas Tower #2 15 6. Nantucket Shoals, Texas Tower #3 17 7 Nantucket Lightship 18 8. Woods Hole, Massachusetts 22 9. Buzzards Lightship 2 3 10. Kingston, Rhode Island 25 1 1. Ambrose Lightship 26 12. Texas Tower #4 (off New York) 30 13. Barnegat Lightship 31 14. Five Fathom Bank Lightship 35 15. Winter Quarter Lightship 39 16. Chesapeake Lightship 43 17. Diamond Shoals Lightship 47 18. Frying Pan Shoals Lightship 51

1 9 Savannah Light ship 55

OCEANOGRAPHIC OBSERVATIONS, 1960 EAST COAST OF THE UNITED STATES

by C. Godfrey Day

ABSTRACT

Daily water temperature and salinity observations for I960 from eighteen locations along the Atlantic seaboard are tabulated, plotted and discussed for the fifth consecutive year.

INTRODUCTION We hope to continue the collection and publication of these data on an annual basis, Through the cooperation of the U.S. Coast and should be glad to include data of a Guard, the Woods Hole Oceanographic Institu- comparable nature from other locations. tion established late in 1955 a series of oceanographic observation posts at a number This work was supported by the Bureau of of lightship stations along the east coast of Commercial Fisheries, U.S. Fish and Wildlife the United States. Additional data have been Service, under Contract No. 14- 17-0007-9 with obtained from independent observers, from the Woods Hole Oceanographic Institution. the Narragansett Marine Laboratory and, courtesy of the U.S. Air Force, from Texas COMMENTARY Towers 2, 3, and 4. Summary for 1956-60 The lightship data have been forwarded on a monthly basis to Woods Hole, where they have Since the present report marks the com- been processed. The bathythermograms have pletion of 5 years of oceanographic observa- been read at several levels and tabulated; tions under this program, a brief description salinities were determined by salinometer. The of results to date is perhaps appropriate. records of air temperature, weather, wind, and clouds were used in studying the other data, Surface Temperature. --Day to day varia- but are not presented here as they are the tions in temperature, sometimes of considera- same as those published in the daily weather ble magnitude, are found at nearly all stations; maps of the U.S. Weather Bureau. these changes are often obscured in the 10- day mean values used for the temperature In addition to tabulating these data, mean profiles in the reports. They are more pro- temperatures for each level for three equal nounced at near- shore stations, where they time periods per month have been determined appear to be the result of tidal action on and plotted, as time-depth profiles for the relatively shallow water which is constantly year at each station where bathythermographs being mixed and subjected to the influence of were used. The one-third monthly mean sur- unmodified continental air. Further offshore, face temperatures have been plotted in com- with the exception of Diamond Shoals, tem- parison with the monthly mean surface temperature is naore stable from day to day. perature for the period of record of each station. With only 5 years of record it is not possible to distinguish between normal and unusual de- The one-third monthly means of surface partures from mean conditions. Temperature salinity have been appended to the tempera- regimes differ at various stations according to ture profiles, together with the weekly bottom the hydrographic geography. salinity values.

The monthly mean surface water tempera- In the annual cycle, warming and chilling of tures for the year I960 for all stations are surface waters are fairly viniform trends with listed in table 1 for comparison with previous few reversals. The more static conditions of records. summer and winter are subject to abrupt, short-ternn changes; these are more pro- We are particularly indebted to the U.S. nounced during the summer when strong winds Coast Guard personnel aboard participating often partially mix a stratified water column. lightships, and to the personnel of the 12th The short-term wintertime changes are less Weather Squadron, USAF, at the three Texas marked; they result no doubt from changes in Towers reporting and at Otis Air Force Base. air tennperature and from advection. Table 1. —Surface water temperatures F - monthly and annual means, I960

Location .

The ThermocIine .--Completely isothermal with only a slight temporal lag. At other water is seldom found at any of the lightship stations further offshore the fluctuations are stations employing the bathythermograph. less extreme and occur later than at the From November through February, bottom inshore stations. water tends to be slightly warmer than surface water since mixing does not keep pace with Monthly mean salinity values between Am- chilling. When vernal warning begins at the brose and Winter Quarter stations increase surface, mixing continues to produce a similar toward the south. Bigelow (1935) drew dia- warming at depth, but again with a lag, so grams of the locations of surface isohalines that a negative gradient is established. The for successive months, based on data from thermocline thus produced is strongest during sections extending offshore across the shelf July and August at a depth between 30 and 60 in this region. While his values increase feet. At stations from Ambrose through Chesa- offshore along a given section, his isohalines peake the temperature gradient is from time curve toward the coast in the Chincoteague to time intensified by advection, possibly region, also showing a southward increase through upwelling, of colder water near the in salinity. bottom. Destruction of the thermocline is directly associated with autumn storms, often Ketchum and Keen (1955) discussed this connected with the passage of hurricanes. phenomenon in a study of the accumulation If such storms occur early in the autumn, the of river water over the shelf in the same thermocline may reappear briefly before the region, concluding that considerable local final overturn. mixing across the shelf must take place. The lightship data tend to confirm this conclusion. Bottom Water Temperature .--Warming and chilling at the bottom are not the steady The annual salinity cycle at the lightship progressions seen at the surface. There are stations reflects the annual precipitation- sharp changes in rate and frequent reversals runoff regime over the east coast. If dynamic in trend. When thermal stratification is pres- gradients from the shore out over the shelf ent, abrupt warming at the bottom is ap- contribute strongly to the circulation patterns, parently the result of wind mixing, as at the there will be large seasonal and year-to-year time of the autumn overturn when bottom values variations in coastal currents. Southwesterly reach their maximum, sometimes rising as movement along shore should be greatest much as 18 F. in 48 hours. Abrupt cooling during April and May at the time of peak appears to be associated with the advection runoff and before the summer southwesterly of colder offshore water. winds become established. During the winter, the dynamic gradient would be weakest.

Salinity . --From Ambrose Lightship north- ward, the surface salinity minimum near Meteorological Effects . --The influence of shore occurs in late April or early May, weather on the hydrography of the area of reflecting the peak runoff augmented by snow study has been demonstrated in several in- melt. At Georges Shoals, farther offshore, stances. Bumpus (1960) showed that runoff is the minimum probably appears in late summer a critical factor in inducing the cyclonic move- From Barnegat Lightship southward the salin- ment in the Gulf of Maine, beginning in late ity minima may occur at any time and nnore winter and early spring. The earlier postula- innmediately reflect local precipitation, since tion of Bumpus and Pierce (1955) concerning there is little storage by freezing on the ad- the penetration of Virginian coastal water jacent watersheds. At most stations. Savannah southward past Cape Hatteras has been sub- excepted, the January and February surface stantiated (Bumpus, 1957; Chase, 1959; Day, salinity readings show little year-to-year 1959). Wells and Gray (1960) found a close difference. correlation between the abundance of Mytilus edulis in the Beaufort, N.C. region in June The two principal factors influencing the and the frequency of northeast storms at salinity regime at the different lightship sta- Cape Hatteras during the reproductive period tions are fresh water runoff from the land of the preceding autumn. Chase has also and incursions of highly saline oceanic water. shown the effect of northeasterly wind regimes The interplay of these forces is most apparent on the temperature structure during the sum- at Diamond Shoals, where Gulf Stream water mer at stations between New York and Chesa- of 36.0 /oo often is replaced in a matter of peake. hours by water of 30.0 °/oo. Only in the broadest terms is it possible The effect of runoff is most noticeable at to see a direct relationship between air Portland, Ambrose, Chesapeake, and Savannah temperature anomalies and trends in water stations, which are near nnajor sources of temperature, except at stations close to shore, outflow. The salinity fluctuations at these e.g., Woods Hole. Consideration of wind stations run parallel to the gaged river flow systems, however, as in the study by Chase (1959) has been more rewarding and leads to spring and summer. November was warm, the conclusion that changes in water tempera- but December temperatures fell well below ture at a given station are often the result the mean. of wind-induced advection rather than in situ modification of water by the atmosphere. Bottom temperature (fig. 1). --During the Day (1960) shows an instance of this happening nearly isothermal months of late winter bottom at Browns Ledge during the summer of 1959. water temperatures reflected surface conditions; values were low but not as low as in The 1960 Data 1958. The summertime intrusion of cold bottom Surface temperature (fig. 1).--The surface water was again apparent from Barnegat water temperature regime from Cape Cod station southward. At most stations maximum to Cape Hatteras was marked by a warm Jan- bottom readings occurred after the autumn uary and February followed by a cold March turnover in late September; values were high, which produced the minima for all stations. probably because of the warm surface condi- This cold period was similar to that in 1958 tions earlier in the month. It is noteworthy though it was less intense and of shorter that except at Barnegat Lightship hurricane duration; the temperature barrier at Cape Donna, which moved up the coast on Septennber Hatteras was weakened but not breached. 11 and 12, failed to mix the water column Recovery was rapid and was followed by completely and that the turnover was not above-the-mean temperatures during the late accomplished until late in the month.

I I I I I I I I I I I I M A M J J ' A S A M J J A S N D I960 I960 SURFACE T. °F BOTTOM T °F

Figure 1.— The cycle of temperature at the surface (left) and bottom (right) along the series of observation posts for 1960. Heavy dotted and dashed lines indicate minimum and maximum temperatures respectively. Mt. Desert Rock Light Station (fig. 2, waters in the Gulf of Maine. In the winter and table 2)--Surface water temperatures from spring months of 1960 values were below the this station are presented for the first time mean; summer readings were near normal. in this series of reports. The small annual The warm November followed by abrupt chilling range in temperature, less than 18° F., is in December was characteristic of conditions probab]y characteristic of the offshore along the entire east coast at that time.

u.- 60

JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SER OCT. NOV. DEC.

figure 2.— Mt. Desert Rock Light Station. (Dashed line mean for period 1925-40.) Table 2. —Mt. Desert Rock Light Station: surface water temperature ( F,) 1960

t43°58.1' N., 68°07.8' W.]

Day Portland Lightship (fig. 3, table 3)--Awarm The surface salinity during February, June and an abrupt depression in surface March, late April, and mid-May were the temperatures in early July represent the lowest on record. River runoff in the New only noteworthy departures from the mean at England area had been above median during this station. Minimum bottom values appeared January, February, and April. (U.S. Geological in mid-March, the maximum in late October. Survey.)

JAN FEB. MAR APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 3.— Portland Lightship. (Dashed line in upper diagram mean for period 1950-59.) Table 3. --Portland Lightship: teniperature (° F. ) and salinity (°/oo), 1960

[43°31.6' N., 70^05. 6' W.; water depth: 160 feet]

Month and Table 3.— Portland Lightship: temperature (° F. ) and salinity (°/oo), 1960— Continued

[43*'31.6' N., lO^OS-SW.; water depth: 150 feed

Itonth Table 3.— Portland Lightship: temperature ( F. ) and salinity ( /oo)» 1960— Continued

[43°31.6* N.. 10°06.5' W.; water depth] ISO fee tl

Itonth Boston Lightship (fig. 4, table 4)--Surface period 1956-60. Bottom water tennperati; water temperatures at Boston are somewhat were in no way unusual. puzzling in that they do not parallel conditions seen at Portland. Winter, spring, and early Surface salinity in May and June was

summer temperatures were above the mean, lowest on record and occurred slightly 1; July below (as at Portland) and August- in the season than the Portland minim September again above. The maximum, how- This probably reflects the southerly moven ever, was the second lowest for the 5-year of surface water along the coast in this reg

JAN. FEB. MAR. APR. MAY JUN. JUL. AuG. SEP. OCT. NOV. DEC.

Figure 4.~Boston Lightship. {Dashed line in upper diagram mean for period 1925-41.)

11 (° Table 4.— Boston Lightship: temperature F. ) and salinity (°/oo), 1960

142°20.4'N.. 70'>16.6'W.; water depth: 96 feet]

Ktonth and Table ^.—Boston Lightship: temperature ( F. ) and salinity ( /oo), 1960 Continued

[42°20.4'N., 70°45.5'W.; water depth: 96 feet]

Month Table ^.—Boston Lightship: temperature ( F. ) and salinity (°/oo), I960. — Continued

[42°20.4*N., 10° 45.b*W.: water depth: 96 feet]

htonth .

Georges Shoal, Texas Tower #2 (fig. 5, previous years through June, after which time table 5)--The minimum temperature in early readings were comparable to those of 1956- March equaled the low of the year before. 59. The winters of 1957 and 1958 had been warmer Warming was slower than it had been in Salinity showed little departure from normal.

34.0 SURFACE S.%o

32.0 JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure S.—Georges Shoal, Texas Tower < 2.

Table 5. --Georges Shoals, Texas Tower 2: temperature { F. ) and salinity { /oo), 196U

[41°'»'16.3"N.. 6T°45"36.2" W,; watei depihi 56 feet]

Itonth -Georges Shoale, Texas Tower 2: temperature ( F.) and salinity (°/oo), 1960—Continued

[41'*4r 16. 3" N.. 67"46*36.2'* W.; wAier depthi 56 fwij tenth Nantucket Shoals, Texas Tower #3 (fig. 6, mid-July. August through October paralleled table 6)--The winter mininnum of 36.4 °F. conditions seen in 1958 and 1959, but Nobember was the coldest since the record began here and December were considerablv warmer. in 1958. Warming appeared to be slow through

ec 50 I-< a: UJ 40 a. SURFACE T. »F 30 _i_ JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SER OCT. NOV. DEC.

Figure 6.— Nantucket Shoals, Texas Tower #3.

Table 6. —Nantucket Shoals, Texas Tower 3: Surface water temperature (° F. 1960 [41°00'52"N., 69°29'37"W.]

Day Nantucket Lightship (fig. 7, table 7)--Sur- It is unfortunate that the winter observations face temperatures were below the mean except were too thin during the cold period in Febru- in late August. This has held true since this ary to allow comparison with similar cold con- progrann started in 1956 and may be attributed ditions seen in 1957. to a change in station position for this lightship. The mean is based on the record from 1947 to 1952 when the station was some 8 miles WSW of the present position.

60 Uj (t K 50 (t Uj a. 40 Uj SURFACE T. °F.

1 m m\ '/]; // 1

60 \

Uj <39° 40° ; \ Uj ^ 80 <45'' g \\\55» \ \\ £ 100 p; Q.

\ 120

140

> ill 160

I !i I

180 _1_JJ

36.0 O »? 34.0 >. BOTTOM S.%<

J 32.0 >? to SURFACE S.%. 30.0 JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 7.--Nantuckel Lightship. (Dashed line in upper diagram mean for period 1947-52.) Table 7.— Nantucket Lightship: temperature ( F. ) and salinity ( /oo), I960

[40°33' 00" N. , e9°28'00"W.; wftter depthi 192 feet]

Month Table 7.—Nantucket Lightship: temperature ( F. ) and salinity ( /oo), 1960 —Continued

(40'*33'00" N.. 69°28'00" W.; w«tti depth: 192 feet]

libnth Table 7. --Nantucket Lightship, temperature (° F.) and aalinity (°/oo}, 1960--Contlnued

[*0°air 00" N. . 69°2fl' 00" W. : waiei depth: 192 feet]

Itonth Woods Hole, Massachusetts (fig. 8, table 8)-- relatively warm conditions of Novennber gave The monthly mean water tennperature for way abruptly to below normal readings in March was the coldest since 1941, and values late December. continued below the nnean through April. The

JAN FEB. MAR. APR. MAY JUN. JUL. AUG. SER OCT. NOV. DEC.

Figure 8.— Woods Hole, MassachusettB, (Dashed line mean for period 1950-59.)

Table 8. —^Wooda Hole, Maflsachufietts: surface teraperatiire (° F) i960 Buzzards Lightship (fig. 9, table 9)-- January Hole. December data were lost in transit. and February surface temperatures were above Salinity during July and August was slightly those of the three previous years, but March lower than those for 1956-59, but there is and April warnning lagged. The slight depres- little annual or year-to-year variation at this sion in mid-August also appeared at Woods station.

34.0 i«

BOTTOM S. %<: 32.0

-J ^ 30.0 JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP OCT NOV. DEC.

Figure 9.— Buzzards Lightship.

Table 9. --Buzzards Lightship: temperature C*^ F. ) and salinity (o/oo), 1960

(41°24'00'"N.. 71 03'00" W.; watex depth: 74 feet]

Month Table 9.—Buzzards Lightship: temperature (^ F. ) and salinity C°/oo), 1960— Continued

[«''24*00*'K., 71°03'00" W. ; water dcpitj 74 fcet]

Month Kingston, Rhode Island (fig. 10, table 10)-- lagged sonnewhat. The rest of the year was As at Buzzards Lightship, January and Febru- average until late Novennber, which was ary temperatures at Kingston were relatively warmer than usual. The sharp drop in Decem- warm, though the subsequent vernal warming ber was seen at other stations.

JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC,

Figure 10.— Kingston, Rhode Island.

Table 10. —Kingston, Rhode Island Narragansett Marine Laboratory Pier: surface water temperature (° F.), 1960

[41°29'32"N.. 70°25"10" W.]

Day Ambrose LJRhtship (fig. 11, table 11)-- in the amount of runoff from the Hudson The presence of a slight and sonnewhat con- River; such variations are clearly shown in fused vertical temperature structure from the surface salinity values. The June data January through March was also seen at this were lost when the Relief Lightship was station during 1957-59, though not in 1956. rammed and sunk, and bathythermograph fail- During this season other stations show nearly ure resulted in the loss of bottom observations isothermal conditions. The difference at during late summer and fall. Ambrose Lightship no doubt reflects variations

Ui 60

40 SURFACE T °F

30 L

n 1 nil

Uj It ^--^l' 'MM 1/ Ml \ I

100

BOTTOM S.%

SURFACE S.%<

24.0 _i_ JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT NOV. DEC.

Figure 11.— Ambrose Lightship. (Dashed line in upper diagram mean lor period 1950-59.)

26 11. Table —Ambrose Lightship: temperature ( F. ) and salinity ( /oo), 1960

[40''27.1' N.. 73°49.4* W. : water depth: 96 feed

ftonth Table 11. —Ambrose Lightship: temperature ( F. ) and salinity ( /oo), 1960. — Continued

t40°27.1* N., 73''49.V W.; wllei deptto 95 feet)

Jfonth Table 11. —Ambrose Lightship: temperature ( F. ) and salinity ( /oo), 1960. — Continued

73°49.4' 95 feet] t40°27.1' N., W. ; water depth:

Ibnth Texas Tower #4 (off New York) (fig, 12, doubtedly reflects advective processes near table 12)- -With only 1959 for comparison, little the boundary of shelf and slope waters. can be said of the tennperature regime at this station. The curve of 10-day mean values Between September 12 and 13 surface tem- shows considerably more fluctuation than would peratures dropped by more than 6° F. as a be expected at an offshore station and vm- result of the passage of hurricane Donna.

80 1 1 70 1 60

50 ll 1 1 1 40

30 September 14 Barnegat Lightship (fig. 13, table 13)-- daily reading was 69.9 F. on Except for below normal surface temperatures after the passage of hurricane Donna. This that storm com- in March and again in December, 1960 was a was the only position where chil- warm year at stations between Barnegat and pletely nnixed the water column. Autumn Cape Hatteras. Temperatures, surface and ling was normal until mid- December, when in bottom, in January and February were above it was accelerated. The salinity nninimum period those of the 1956-59 period; in terms^ of late May was the lowest for the 5-year 10-day means the bottom maximum of 68 F. 1956-60. Only a trace of the expected summer is in mid-September was the highest so far intrusion of cold water along the bottom recorded for the Barnegat station. The highest apparent in the isothernns.

80 '

70-

Uj 50 5 Table 13. — Bamegat Lightship: temperature ( F. ) and salinity ( /oo), 1960

[39°45.8' N., 73°56.0* W.; water depth: 72 feet]

Mjnth Table 13. — Bamegat Lightship: temperature ( F. ) and salinity ( /oo), 1960. — Continued

[39°45.8* N., 73°56.0' W. ; water depth: 12 feel]

Month and (° (°/oo), 1960. —Continued Table 13.~Bamegat Lightship: temperature F. ) and salinity

I39''45.8' N., 73°56.0" W.; water depthj 72 feefl

Month Five Fathom Bank Lightship (fig. 14, table in early June and early July. The 10-day mean 14)--March, early April, and late December bottom maximum of 68. 4° F. was the highest surface water temperatures were below the recorded in 5 years. Salinity was slightly mean at Five Fathom Bank, while May through lower than usual in the early autunnn, but October readings were above. At the bottom otherwise showed little departure from the two separate intrusions of cold water appeared previous records.

34.0 sl r

t 32.0 SURFACE S.%o 5 30.0 I I JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 14.--Five Fathom Bank Lightship. (Dashed line in upper diagram mean for period 1950-59.)

35 Table 14.—Five Fathom Bank Lightship: temperature (° F. ) and salinity (°/oo), 1960

I38°41.3' N., 74''34.6' W.; water depth: 87 feet)

Month rable K.— Five Fathom Bank Lightship: temperature (° F. ) and salinity (°/oo), k960--Continued

138°41.3' N., 74°34.6' W.; water depth: 87 feet]

Month Table 14. --Five Fathom Bank Lightship: ten^ierature (° F. ) and salinity (°/oo), 1960--Continued

[38°47.3* N., 74°34.6' W.; water depth: 87 feeO

Month occurred Winter Quarter Lightship (fig. 15, table 15)-- trusion of cold bottom water probably The surface water temperature regime at during the month. The bottom temperature of highest Winter Quarter was similar to that at other 68.6° F. in late September is the the 5 years of this program. stations in that conditions were generally above recorded in salinity from mid-September the mean except during March. July data The surface was considerably lower were lost owing to instrument failure, but the through mid-October while the depression in inflection of the isotherms on either side of than in other years, precedent at this station. the gap in the profile indicate that an in- mid- December has no

J 34.0 r BOTTOM S.7o

JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT NOV. DEC,

Figure 15.~Winter Quarter Lightship. (Dashed line in upper diagram mean for period 1925-40.)

39 Table 15.— Winter Quarter Lightship: temperature (° F. ) and salinity {°/oo) 1960

[37°55'05"N., 14°5F04"W.; Water deptlu 96 feetj

Vbnth Table 15. --Winter Quarter Lightship: temperature (° F. ) and salinity (°/oo), 1960--Cont

[3f 56' 06" N., 14°56'04" W.; Water depth: 96 (eefl

Utonth and Table 15. —Winter Quarter Lightship: temperature (° F.) and salinity (°/°o), 1960—Continued

137 56' 05" N., 14 56' 04" W.i water depth; 96 feet]

Month and day Chesapeake Lightship (fig. 16, table 16)-- the trends at all stations to the north as Th^ drop In surface water temperature in far as Barnegat Lightship, while to the south March equaled the record low of 1958 at this of Cape Hatteras different conditions prevailed. station; May through October values, however, The cold water intrusion at the bottom in were above the mean, while December was midsummer is now considered normal as are below normal. This regime closely parallels the relatively extrenne salinity fluctuations.

BOTTOM S.%

26.0 JAN. FEB. NflAR. APR. MAY JUN. JUL. AUG. SEP. OCT NOV. DEC.

Figure 16.— Chesapeake Lightship. (Dashed line in upper diagram mean for period 1950-59.)

43 Table 16. --Chesapeake LightsMp: temperature ( F.) and salinity ( /oo), 1960

136°58' OT N. , 76°42* 02" W. ; water depth; 65 feet)

Klor.th Table 16. — Chesapeake Lightship: temperature (° F.) and salinity (°/oo),1960—Continued

[36°58'0r'N.. 75°42*02"W.; water depth: 65 feeO

Month and 16. ) Table —Chesapeak Lightship: temperature ( F. and salinity ( /oo) . 1960—Continued

[36°58' or* N. , 76°42' 02" W.; water depth: 65 feet]

Month Diamond Shoals Lightship (fig. 17, table 17)-- in 1957 and 1959 no such breach of the Because of the complicated thermal structure temperature barrier appeared. The remainder at Diamond Shoals, marked by rapid changes, of the year showed no marked deviation from the profile of temperature is contoured for the mean for this station. The relatively cold every 5 F. November and warm December is a reversal of the trend at positions further to the north. The low surface water temperatures in The bottom temperature maximum, 77.8° in March, which represents the passage of coastal early October, is the highest for the period water southward over the Shoals, has occurred 1956-60. Wide salinity fluctuations asshownin- every other year during the winter months the figure are normal here. since 1956 when these observations began;

It- 80

60 ^^- CL

50 SURFACE T. °R 40

n I I 60° 20

I I 40

60 I- Uj 60° Ul 50° i^ 80 60" >65° £ 100 Q. QUl 120

140

160

180 J L.

38.0 r BOTTOM S.%o

JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 17.~Diamond Shoals Lightship. (Dashed line in upper diagram mean for period 1923-56.)

47 (° /oo), 196C Table 17.—Diamond Shoals Lightship: teniperature F. ) and salinity (

[36*'05'30" N., 15*'l9'30" W.; waici depthj 200 feeC kbntb (° 1960—-Continued Table 17 . --Diamond Shoals Lightship: temperature F.) and salinity ( /ooj,

ISS'^OS'aO" N., 75°19*30" W.; water depih: 200 feel]

(tonth and daj Table 17.--DlaiBond Shoals Llghtahlp: temperature {° F.) and salinity (°/oo)» ^^^O — Continued

tSe^Oe'SO" N., 76°19'30" W.; w«ci

Hon til and 1

Frying Pan Shoals Lightship (fig. 18, table temperatures reach the mean again. The bot- 18)--The cold surface water of late February tom maximum in early September of 81.8° F. and March probably represents a flow of equaled the 1958 high. The intrusion of colder coastal water southward past Cape Hatteras, water near the bottom in summer is an annual as occurred in 1958. Not until June did phenomenon.

n- 90

I 1>llt °n II' I ll \i lllll' |l II 20 I U^ I llllll 65" 60* ^-J 60f, ^oTi

40 H n 1

u> 60 Ivl 1/ I 1

ill I I

K 3ao BOTTOM S.%o

SURFACE S.%o

JAN. FEB MAR. APR MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 18.--Frying Pan Shoals Lightship. (Dashed line in upper diagram mean for period 1950-59.)

51 Table 18. —Frying Pan Shoals Lightship: temperature (° F. ) and salinity (o/oo), 1960

[33°28'00"N. n<'33'08"W.; water depth: 62 feet]

Month Table 18. — Frying Pan Shoals Lightship: temperature (° F.) and salinity (°/oo), I960—Continued

[33°28' 00" U. n<*J- 08" W.; water depth: 72 feet]

Month Table 18.—Frying Pan Shoals Lightship: temperature (° F. ) and salinity (°/oo), 1960—Continued

[33°28"00" N., Tfiaa'OS" W. ; water depth: 62 feefl of 45.5 F. Savannah Lightship (fig. 19, table 19)-- exceeded in 1958 by a 10-day mean Temperatures remained low There is no record of temperature at depth at in February. Savannah during January or February owing to through June, but were generally above the bathythermograph failure. The minimum sur- mean in the autunnn until mid-December. for this station. face temperature in March of 48.9 F. was Surface salinity was "normal"

SO-

Q: TO

^ 60 - ^ y/

Uj SURFACE T. °H 50

Or ll I Uj ^84'. Uj \ II ll I U. \ M |l I 20 \ll illl 180' III 60?

III

' ' 40 K83\l III 'l' J_ Ml I lii iJli

2ao JAN. FEB. MAR. APR. MAY JUN. JUL. AUG. SEP. OCT. NOV. DEC.

Figure 19,"Savannah Lightship. (Dashed line in upper diagram mean for period 1950-59.)

55 Table 19. —Savannah Lightship: tenjierature (° F. ) and salinity (°/oo), 1960

[Sl'ae. 6' N. 80''39. 6' W.: witer depth; 48 teed Continued T^ble 19.— Savannah Lightship: tenrperature ( F. ) and salinity ( /oo), 1960—

[31056.5*N. 80O39.6* W.; water depUu 48 feet] Table 19. —Savannah Lightship: temperature ( F. ) and salinity ( /oo), 1960— Continued

(31056. 5' N. 80O39.6'W.; watei depth; 48 (eetl LITERATURE CITED

BIGELOW, HENRY B., and MARY SEARS. DAY, C. GODFREY. 1935. Studies of the waters on the Conti- 1959. Oceanographic observations, 1958, nental Shelf. Cape Cod to Chesapeake east coast of the United States. U.S. Bay. Part II. Salinity. In Physical Fish and Wildlife Service, Special Oceanography and Meteorology, Massa- Scientific Fisheries--No. 318, 119 p. chusetts Institute of Technology and Woods Hole Oceanographic Institution, 1960. Bottom water temperature on Brown's Cambridge, Massachusetts, 94 p. Ledge off southern Massachusetts. BUMPUS, D. F. Journal du Conseil, vol. 25, no. 3, 1957. Oceanographic observations, 1956, p. 235-239. east coast of the United States. U.S. Fish and Wildlife Service, Special KETCHUM, B. H., and D. JEAN KEEN. Scientific Report--Fisheries No. 233, 1959. The accumulation of river water 132 p. between Cape Cod and Chesapeake Bay. I960. Sources of water contributed to the In Marine Biology and Oceanography, Bay of Fundy by surface circulation. Deep-Sea Research, Supplement to Journal of the Fisheries Research Board Volume 3, p. 346-357. of Canada, vol. 17, no. 2, p. 181-197. BUMPUS, D. F., and E. L. PIERCE. UNITED STATES GEOLOGICAL SURVEY. 1955. The hydrology and distribution of chaetognaths over the Continental Shelf WELLS. HARRY W., and I. E. GRAY. off North Carolina. Deep-Sea Research, 1960. The seasonal occurrence of Mytilus Supplement 3, p. 92-109. edulis on the Carolina coast as the CHASE, JOSEPH. result of transport around Cape Hat- 1959. Wind-induced changes in the water teras. Biological Bulletin, vol. 119, column along the east coast of the no. 3, p. 550-559. United States. Journal Geophysical Re- search, vol. 64, no. 8, p. 1013-1022. MS #1121

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