Upgrades to the Real-Time TMPA G.J. Huffman 1,2, D.T. Bolvin 1,2, EJ. Nelkin 1,2, R.F. Adler 3, E.F. Stocker 1 1: NASA/GSFC Earth Sciences Division 2: Science Systems and Applications, Inc. 3: Univ. of Maryland College Park/ESSIC 1. TMPA SYSTEM - Data Sources and Processing A diverse, changing, uncoordinated set of input precip estimates, with various periods of record regions of coverage sensor-specificstrengths, limitations Seek the longest, most detailed record of “global“ precip Combine the input estimates into a “best” data set Run twice: (near-)real time (~8 hr after observation time) research quality (~2 months later, after “all” data are received) the focus here is the real-time 3. RT FEATURES THAT REMAIN THE SAME Computed on coincident 3-hr, 0.25° data in the band 50°N-S for uncalibrated (RT(U)) and calibrated 3B42RT (RT(C)) against the production Version 6 3B42 (P) Lacking Version 7, we show the performance for Version 6, which should be similar Better values are colored in green Bias mixed results global values are just a small residue of larger regional differences worse global-average bias could result from improvement mainly in regions of one sign RMS calibrated version almost always better implies improvement in most regions Boreal cold season (Jan 2007, Dec 2008) calibrated land is marginally worse for both Bias and RMS most land is in the Northern Hemisphere – believed to reflect relatively large cold-season errors The new Version 7 Real-Time TMPA is being readied for release approx. calibrated to the Version 7 production post-real-time TMPA includes upgrades to most input data sets includes SSMIS input data for the first time provides retrospectively processed data starting in Feb The expected release date for RT is late Spring 2012 the pacing item is completing computation of climatological calibrations to the Version 7 calibrators thereafter, both retrospective processing and processing for new data can begin Version 6 RT processing will continue during the switch-over 4. FINAL REMARKS Native binary trmmopen.gsfc.nasa.gov 3B40RT: microwave precipitation, error, pixel counts, source 3B41RT: IR precipitation, error, pixel counts 3B42RT: combined microwave/IR precipitation (both original and calibrated to 3B42), error, source KMZ (for Google Earth) trmmopen.gsfc.nasa.gov 3B42RT: combined microwave/IR precipitation(calibrated to 3B42) Flat binary through TOVAS 3B42RT: combined microwave/IR precipitation (calibrated to 3B42) Text through TOVAS 3B42RT: combined microwave/IR precipitation (calibrated to 3B42) TOVAS on-line visualization 3B40RT: microwave precipitation 3B41RT: IR precipitation 3B42RT: combined microwave/IR precipitation (calibrated to 3B42) A Note on Terminology General approach: TRMM Multi-satellite Precipitation Analysis [TMPA] Real-time product: 3B42RT [RT], providing two precipitation fields original multi-satellite, without climatological calibration [RT(U)] multi-satellite with climatological calibration, [RT(C)] Version 7 post-real-time production product: 3B42 [P] A Note on Terminology General approach: TRMM Multi-satellite Precipitation Analysis [TMPA] Real-time product: 3B42RT [RT], providing two precipitation fields original multi-satellite, without climatological calibration [RT(U)] multi-satellite with climatological calibration, [RT(C)] Version 7 post-real-time production product: 3B42 [P] Instant - aneous SSM/I TRMM AMSR AMSU HQ coefficients 3-hourly merged HQ 3- hourly IR Tb Hourly HQ-calib IR precip 3-hourly multi-satellite (MS) Monthl y gauges Monthly SG Rescale 3-hourly MS to monthly SG Rescaled 3-hourly MS Calibrate High-Quality (HQ) Estimates to “Best” Merge HQ Estimates Match IR and HQ, generate coeffs Apply IR coefficients Merge IR and HQ estimates Compute monthly satellite-gauge combination (SG) 30-day IR coefficients Monthl y Climo. Adj. Coeff. Processing Sequence Both RT and P computed on a 3-hr 0.25° grid Microwave precip: intercalibrate, combine IR precip: calibrate with microwave Combined microwave/IR: IR fills gaps in microwave Both RT and P calibrate the initial 3-hr MS RT does monthly climatological calibration on 1° grid TMI-TCI calibration first, then gauge uses 10 years of match-ups, broken into monthly fields Both RT and P will archive both uncal. and cal. 3-hr MS Upgrades and Reprocessing Episodically, the TMPA is upgraded to take advantage of new/revised input data improved processing concepts Ideally, upgrades are accompanied by reprocessing to ensure consistency of the entire data set built in to P system new concept for RT – this is the first time Bias (mm/d)RMS (mm/d) RT(U)-PRT(C)-PRT(U)-PRT(C)-P Land Ocean All Land Ocean All Land Ocean All Land Ocean All Land Ocean All Land Ocean All Land Ocean All Dec’08 Nov’08 Oct’08 Oct’07 Jul’07 Apr’07 Jan’07 V7 vs. V6 P – July RT ENHANCEMENTS FOR VERSION TMI 2002 SSM/I F14 SSM/I F13 SSM/I F15 AMSU N16 AMSU N15 AMSU N17 AMSR-E CPC Merged IR 2006 SSMIS F16 MHS N18 MHS N19 SSMIS F MHS MetOp SSMIS F Original RT 2002 Retrospective Version 7 RT Users requested this to provide an extended data record with consistent processing for quantitative work (hydrology, crop forecasting) Most existing input data sets are upgraded Additional periods of record are included (boxes) some parts of the data records are not suitable – shown with lighter-color lines SSMIS is used for the first time Dotted vertical line indicates start of CPC Merged IR dataset the P before this time depends on a different IR data set not considered in the RT The previous RT record was inhomogeneous in time black hash marks denote substantial changes in input data types, input data algorithms, or RT processing the only fully consistent record was October 2008 – present without reprocessing, the changes listed above would have implied starting over with a new, different data series when Version 7 RT starts (in 2012) Retrospective processing provides a uniformly processed 12-year record P is still the dataset of choice for research – the goal here is to facilitate calibration of real-time applications There are still caveats: changes in the satellite constellation still create potential inhomogeneities the retrospective processing for RT will be run on the P input data, introducing the possibility of small differences compared to running in real time on the RT input data Lacking Version 7 RT, we compare an example month of Versions 6 and 7 P, which should be similar to comparing Versions 6 and 7 RT Comparing Version 6 to Version 7 P for July 2008 (general product name is 3B43) this is the first sample month Version 7 tends to be somewhat higher over ocean the Southern Ocean is lower, perhaps due to seasonal effects? changes over land should be driven by differences in the gauge analysis Version 6 gauge for this month is CAMS; Version 7 gauge is GPCC throughout dramatic changes in the Indian Monsoon area are likely due to data gaps in CAMS Version 7 values are considered better V7 3B43 Jul 2008 (mm/d) V6 3B43 Jul 2008 (mm/d) (V7) – (V6) Jul 2008 (mm/d) Comparing Version 6 and Version 7 P to atoll gauge data for July 2008 atoll data from the PACRAIN archive at Univ. of Oklahoma the western tropical Pacific yielded 8 atolls, each corresponding to a 0.25°x0.25° grid box of P data the average biases are: Version 6: mm/d (-20%) Version 7: mm/d (-7%) consistent with maps above RT Format Remains the Same RT Is Again Climatologically Calibrated to P Version 7 RT Will Include Retrospective ProcessingUpgraded Input Data Should Yield a Better Product in Version 7 Questions or to to be put on the notification list: Web pages: 3B42/43 document:ftp://meso.gsfc.nasa.gov/pub/trmmdocs/ 3B42_3B43_doc.pdf 3B4xRT documents:ftp://meso.gsfc.nasa.gov/pub/trmmdocs/rt/ Poster PT-2