Goodman Et Al GLM Atmos Res 2013.Pdf

and ground segment. GOES-R is scheduled for launch in late 2015,Atmospheric and the Research second satellite (GOES-S) is scheduled for launch in 2017.

The GLM detection efficiency is expected to exceed the 70% performance requirement with flash detection perhaps as high as 90%. This is accomplished, in large part, by increasing the telemetry downlink rate to 7.7 mbps which allows for a lower threshold setting to detect weak lightning optical pulses and ground processing that will filter out the non- lightning events. The telemetry downlink is sized to also accommodate the background data, which are reported every 2.5 min to aid in navigation and registration. While the LIS used similar filters in its ground processing algorithms, the LIS only had a telemetry bandwidth of 8 kbps and needed a higher threshold setting to avoid buffer overflow and saturation during overpasses of storms with high flash rates. Because the GLM is an operational instrument, minimal latency is important. The instrument vendor is allocated 10 s to collect, filter, geo-locate and time tag the raw data into Level 1B lightning events. After Level 1B processing the(instru¬ment existing GOES data constellation at full resolution currently with operating radiometric over and the Western geometric Hemispherecorrection applied (http://www.goes-r.gov to produce parameters). The GOES-Rin physical system units), is the a Level joint 2 developmentLightning Cluster between Filter the National Algorithm Aeronautics (LCFA) described and Space in Administration the GLM AWG (NASA)Algorithm and the Theoretical National BasisOceanic Document and Atmospheric (ATBD) performs Administration temporal–spatial (NOAA) withclustering NASA of responsible the lightning for event the data space into groups segment (akin (spacecraft to return strokes and instruments)and k-changes) and NOAAand flashes responsible (Mach foret al., the 2007; overall Goodman program et al., 2012a,b). Fig. 3. The Geostationary Lightning Mapper (GLM) consists of a sensor unit (SU) and electronics unit (EU). An engineering development unit prototype was developed before the first production flight model (FM1) to reduce risk in the instrument development.

The concept of the LCFA is closely based on the heritage OTD/LIS data processing algorithm in that it builds a parent–child tree-structure that identifies the clustering of optical events into groups, and groups into The LCFA only requires the Level 1b pixel-level event data as input. flashes (Fig. 4). The three components of the GOES-R Lightning Detection This includes the event pixel time-stamp, the (x, y) pixel address within product (event, group, flash) provide continuity with the combined the focal plane array, the associated geolocation of the center of the LIS/OTD climatology that begins in April 1995 with the launch of the OTD. event in latitude/longitude coordinates, the raw event amplitude in This component information can then be used to locate the initiation, counts, and the calibrated event optical energy (in Joules). The input data propagation and horizontal extent of an individual flash within the GLM are time ordered. field of view. Theentire data production chain from event detection at the To obtain this dataset, the satellite data stream needs to be decoded, satellite to user access via satellite downlink from the GOES Rebroadcast filtered, and clustered, and output to the appropriate file. The LCFA only (GRB) or the NOAA Satellite Operations Facility (NSOF) is designed to be generates the lightning dataset. Specifically, the LCFA receives as input <20 s. the LevelA lightning1b pixel-level discharge optical will “event” often illuminatedata and processesmore than this one data pixel into during more convenient lightning data products that are easily utilized by the a single integration time. The result is two or more adjacent events within scientificthe same research time andframe. broader When operational these multiple user eventscommunities. are adjacent Therefore, to each theother LCFA (a must side ingestor corner the of event the events data andtouching), assemble they the will higher be placed level in a clusteredsingle lightninggroup. The data formal products definition (event, of groupa group and is oneflash), or andmore in simultaneous so doing, generateevents derived (i.e., events lightning that characteristicsoccur in the same associated time integration with these frame) higher that levelregister products. in adjacent It will also(neighboring interrogate or individualdiagonal) pixels flashes, in groups,the focal and plane eventsarray. on Aa groupstatistical may basis consist to ofsee only if they one are event associated or include with many lightning events. or The location data for a group will be calculated in Earth-based (latitude/ 3.longitude) Ground Processingcoordinates. AlgorithmsThis is done to provide consistent representation noise.in the Definitions group/flash of the processing basic data\classes and because that the drive ultimate the LCFA goal are of the providedanalysis below. is to locate lightning with respect to the Earth's surface. Fig. 4. Optical groups attempt to track bright transient emissions from lightning. Inter-stroke processes (return strokes, k-changes) also produce optical groups [Photograph is of a 12-stroke lightning flash near Socorro, New Mexico; Marx Brook, New Mexico Institute of Mining and Technology]. Field campaigns provide valuable opportunities to collect more comprehensive data sets than are usually affordable or achievable by one investigator or even a single mission or agency. Inter-agency and 4.2. Cal/val ﬁeld campaigns 4.Fig. internationalCalibration/validation 5. Illustration of field a single campaigns GLM flash have composed a long of 2 historygroups and of 20 providing events relative these opportunities to leverage resources. For GOES-R, and GLM in particular, Thewe goal expect of GLM a number validation of is pre-and to ensure post-launch that GLM experimentsproduct components that can (event,augment group, the flash) GLM are Testbed adequately super detected site data and sets, accurately for developing located more in spacerobust and and time realistic within theproxy required data as latency. well as Assessments for algorithm are validation. determined The (primarily)challenge by for comparisons GLM is that to therea variety is no of current external geostationary (independent) lightning data sourcesmapper of tocomparable serve as a orsource higher of accuracyproxy data, in unlikelocations the for case which for the we GOES-R have ABI where quite extensive and representative proxy data sets can be overlappingdeveloped regionsfrom the of geostationary coverage. As GOES, the GLM MTSAT has (Japan), a large or region Meteosat of coverage,Second aGeneration variety of techniques (MSG) 12-channel need to SEVIRIbe applied (Spinning in varying Enhanced parts of Visible its domain,and Infrared depending Imager), on the or reference the NASA data's 32-channel characteristics. Moderate The Resolution LCFA algorithmImaging validation Spectroradiometer addresses (MODIS)several factors and recently including launched accuracy 22-channel of the scientificVisibleThe results InfraredGOES-R produced ProvingImager byGroundRadiometer the algorithm, is both Suite a valueuser (VIIRS) and of withthe developer scientific high spectral of results, satellite and computationalrelatedspatial training.resolution speed The in of participantslow the Earth algorithm, orbit. in the feasibilityThus, Proving the OTDofGround testing and activities LIS the overpasses algorithm need to of (clarity/completenessunderstandinstrumented the ground characteristics of sites algorithm present of the performanceone proxy of theGOES-R better metrics, products opportunities ability and their to to The GOES-R Proving Ground is one of the primary means to accelerate generateutilitydevelop within laboratoryand NOAA'svalidate demo operational the pre-launch results environment. using algorithms simulated The for GLM.knowledge data inputs), user's and gain user readiness for the new capabilities that will be provided by the GOES- feasibilityin applying A recentof implementing these opportunity products the to isalgorithm thencollect passed moreon-orbit. backcomprehensive to product lightning developers, and A recent study of over 700 storms by Schultz et al. (2011) further GOES-R ancillary For GLM and meteorological products,other NOAA the data program validation took managers,place includes between andcomparison toNovember the broaderwith 2011 other user and supports the potential value of monitoring total lightning activity availablecommunitiesMarch data,2012 inmonitoringoutside southeast of LCFANOAA. Brazil data during Forecasters quality, the CHUVA and participating statistical (Cloud processes analysis.in the GOES-R Theof tHe applicable to the GLM to increase tornado and severe storm warning lead- GLMProvingmain results precipitation Ground will be at compared thesystems NOAA toin HazardouscloudBrazil: and A contribUtion otherWeather lightning Testbed to datacloud are to resolVing verifyalready time and reduce the false alarm rate (Williams et al., 1999; Schultz et al., themodeling GLM perfor¬mance. and to the GPMThe LCFA(GlobAl monitoring Precipitation flags Measurement))(metadata) in the Vale L2 do 2009; Gatlin and Goodman, 2010). The current operational warning dataParaíba stream field indicate campaign. problems The CHUVA such as experiment when clustering6.3. domain Training processing of southeast¬ern was approach relies heavily on weather radar signatures and visual cues from truncatedfindingBrazil is the toone total meet of the lightning processing more active data latency useful thunderstorm limits.in the Thewarning regions statistical decision-makingin the analysis Americas stormprocess,(Pinto spotters, et quoting al., resulting2007; from De forecastersinSouza a national et al., as 2009).average follows: tornado warning lead-time Rassesses satellite the series reasonableness (Goodman et of al., lightning 2012b; productRalph et statistics. al., in press). To ensure The primary science objective for the GLM-CHUVA light¬ning mapping user • The readiness, GLM lightningIn forecasters terms product of and operational validationother users utility, will must make forecasters have use access of available noted to prototype thatspace- the campaign is to combine measurements of total lightning activity, lightning advancedbasedPseudo observations Geostationary products within from Lightning thetheir LIS operationalMapper and from(PGLM) environment the total following light¬ning well additional beforeproxy (as channel mapping, storm micro¬physics, and meteorological data to launch.sources:viewed Examples (1) from available of the the 1-minuteadvanced satellite products flash lightning extent include photometers density) improved showed such volcanic as “goodash the detection,FORMOSAT-2correlation”withimprove 1-minour Imager understanding interval“updraft of Sprites intensity” rapid ofand thunderstorms. scan Upper and imagery, was Atmospheric typically The convective measurementsseen Lightning “well initiation, (ISUAL)ahead from of syntheticexperimentthethe first 3D cloud CG”total and (cloud-to-ground) andlightning TARANIS moisture mapping (Tool imagery, flash. fornetworks Additionally, the and Analysis includelightning the ofa detection.NASA-deployedtotal RAdiation lightning A from key data São component“pulled focus of the to GOES-R individual Proving storms”of Ground interest. is the two-wayThis was interactionparticularly useful lightNIngPaulo Lightning and Sprites), Mapping (2) high Array altitude (SPLMA) long-duration and a number airborne of regional optical and and betweenduring the days researchers that the who weather introduce was new marginally products severe and techniques with numerous electricalstorms acrossmeasurements the county from warning an Airborne area of operations. GLM Simulator package that can be flown aboard the NASA ER-2 and Global Hawk UAV, and (3) ground-based lightning and electric field-change detection networks including one or more super-sites such as north Alabama and central Oklahoma where diverse meteorological instrumentation is available for characterizing lightning and their parent storms (Table 2).

4.1. Proxy data

Proxy data and test data sets have been generated from several sources. Some proxy datasets are based on National Lightning Detection Network (NLDN; Cummins and Murphy, 2009) data, some are based on empirically mapping ground-based VHF 3-D Lightning Mapping Array (LMA; Rison et al., 1999) data into optical data, some are based on simply resampling heritage LIS data (Mach et al., 2007) into the GLM FOV and Two higher order GLM-based lightning products described here, a pixel spacing, and some are based on artificial sources. Each type of proxy pseudo With GLM higher (PGLM) resolution flash global extent and density regional product cloud-resolving and NSSL-WRF numerical is used to test different parts of the LCFA and can be used to test simulatedweather prediction lightning threat models forecast (e.g., Weather (McCaul Research et al., 2009 and), Forecast, have been High subsequent application algorithms (Gatlin and Goodman, 2010; Schultz et undergoingResolution Rapid evaluation Refresh) at and the advanced NOAA Hazardous 3DVAR, 4DVAR, Weather Ensemble Testbed Kalman in al., 2009, 2011). Norman,Filter (EnKF), OK ( Fig.and 11hybrid). data assimilation methodologies in widespread use References

GLM represents the first operational mission in this family and is designed for 5 years of on-ground storage, 5 years of on-orbit storage, and 10 years of operations while meeting key performance requirements through the mission end-of-life. The initial check-out and post-launch testing will be a minimumof6 monthsindurationat90°Wlongitude,followed by planned on-orbit storage at 105 W until GOES-R is called into service as a replacement for the current GOES. Users will be able to access the

The GLM represents the next step in the global observing system for continuous operational high fidelity measurements of lightning on Earth. The GLM flight model #1 is scheduled for delivery in 2013 for integration onto the GOES-R spacecraft for a planned launch aboard an Atlas-V 541 rocket at the end of 2015. The ground processing algorithms are an extension of the algorithms developed for the earlier OTD and LIS Chronis,research T.G., Goodman, instruments S.J., Cecil, in lowD., Buechler, Earth orbit. D., Robertson, Concepts F.J., for Pittman, the GLM J., Blakeslee, have been R.J., 2008.explored Global sincelightning the activity early from 1980s the ENSO culminating perspective. with Geophys. the singleRes. Lett. telescope 35, L19804.design http://dx.doi.org/10.1029/2008GL034321 having high detection efficiency. for total lightning approaching 90% with near uniform storm-scale spatial resolution owing to the variable pitch pixel detector design. The high detection efficiency is made possible by the data telemetry bandwidth of 7.7 mbps that allows the GLM to be set at a more sensitive (lower) detection threshold and transmit 100,000 events per second (nominally 40,000 lightning events and the remainder noise) to the ground where the ground processing algorithms filter out the non-lightning events. GOES-R data through four primary pathways as follows:

• GOES-R Rebroadcast (GRB) —the primary low-latency satellite direct distribution for Level 1b products. For GLM the Level 1B and Level 2 Lightning Detection Product components (event, group, and flash) are broadcast as a streaming data set by the GRB.

Zipser, E.J., Cecil, D.J., Liu, C., Nesbitt, S.W., Yorty, D.P., 2006. Where are the most intense thunderstorms on earth? Bull. Amer. Meteorol. Soc. 87, 1057–1071.

Goodman, S.J., Buechler, D., McCaul, E., 2007. Lightning. In: King, M., Parkinson, C., Partington, K., Williams, R. (Eds.), Our Changing Planet: the View from Space. Cambridge University Press, pp. 44–52.