Data Access:
TRMM Microwave Imager (TMI) Level 2A Hydrometeor Profile Product 2A12: http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&project=TRMM&dataGroup=Orbital&dataset=2A12:%20Hydrometeor%20Profile%20%28TMI%29&version=006
| The latent heating products of TRMM 2A12 and 3A12 over ocean surfaces should be regarded as experimental.Please confer first with the algorithm developers (by contacting the GES DISC) when using the latent heating product over ocean.Over-land latent heating estimates from TRMM products 2A12 and 3A12 should not be used, as they have not been evaluated quantitatively or qualitatively. | Contents: This document provides basic information on 2A12, TRMM Microwave Imager (TMI) Level 2 Hydrometeor Profile Product. The TMI profiling algorithm (2A12) generates vertical profiles of hydrometeors from TMI brightness temperatures by blending the radiometric data with dynamical cloud models. For each pixel, the algorithm assigns a surface type (land/ocean/coast) and a freezing height; and computes surface rain, convective surface rain, and profiles of hydrometeors (cloud liquid, cloud ice, water vapor, etc.) at 14 vertical levels. TMI Level 1A ==> 1B11 Calibrated TMI brightness temperatures ==> 2A12 TMI Rainfall Structure The data flow of all products are shown in Satellite Algorithm Flow Diagram. Data Characteristics
| TRMM 2A12 (TMI) Data Characteristics | | | Pre-boost (before 08-07-2001) | Post-boost (after 08-24-2001) | | Temporal Coverage | Start Date: 12-08-1997
Stop Date: 08-07-2001 | Start Date: 08-24-2001
Stop Date: - | | Geographic Coverage | Latitude: 38°S - 38°N
Longitude:180°W - 180°E | Latitude: 38°S - 38°N
Longitude:180°W - 180°E | | Vertical Coverage | Surface - 18 km | Surface - 18 km | | Temporal Resolution | About 91.5 minutes per orbit
About 16 orbits per day
More information about revisit frequency | About 92.5 minutes per orbit
About 16 orbits per day
More information about revisit frequency | | Horizontal Resolution | 4.4 km at 85.5 GHz | 5.1 km at 85.5 GHz | | Vertical Resolution | 0.5 km from surface to 4 km
1.0 km from 4 to 6 km
2.0 km from 6 to 10 km
4.0 km from 10 to 18 km | 0.5 km from surface to 4 km
1.0 km from 4 to 6 km
2.0 km from 6 to 10 km
4.0 km from 10 to 18 km | | Scan Characteristics | Swath Width: 760 km
Pixels/Scan: 208
Scans/Second (SS): 36.100/60
Seconds/Orbit (SO): 5490
Average Scans/Orbit: nscan = SS*SO+100 = 2991 | Swath Width: 878 km
Pixels/Scan: 208
Scans/Second (SS): 36.100/60
Seconds/Orbit (SO): 5550
Average Scans/Orbit: nscan = SS*SO+100 = 3023 | | Average File Size | Compressed: ~8.5 MB
Original: ~102 MB | Compressed: ~8.5 MB
Original: ~103 MB | | File Type | HDF | HDF | Data Format Structure The following table summarizes the contents and structure of the TMI rain profile (2A12) product. Further information can be found in Volume 4 of the "File Specifications for PPS Products - Level 2 and Level 3" . | Data Format Structure for 2A12, TMI Profiling | | Name | Type | Record
Size
(byte) | Dim Size
(# of Records) | Scaled
by | Range | Unit | Description | | ECS Core Metadata | Char Attribute | 10,000 | - | - | - | - | ECS Core Metadata. | | PS Metadata | Char Attribute | 10,000 | - | - | - | - | Product Specific Metadata. | | Swath Structure | Char Attribute | 5,000 | - | - | - | - | Specifications for the swath geometry. | | Scan Time | Vdata Table | 9 | nscan | - | - | - | Time associated with each scan. | | Geolocation | Float SDS | 4 | 2*npixel*nscan | - | - | degree | Earth location of the center of the IFOV at the altitude of the earth ellipsoid. The first dimension is latitude and longitude, in that order. The next dimensions are numbers of pixels and scans. | | Scan Status | Vdata Table | 21 | nscan | - | - | - | Status of each scan. | | Navigation | Vdata Table | 88 | nscan | - | - | - | Spacecraft geocentric information. | | Data Flag | Integer SDS | 1 | npixel*nscan | - | - | - | Indicates the quality of data. | | Rain Flag | Integer SDS | 1 | npixel*nscan | - | - | - | Indicates if rain is possible
>=0 : rain is possible;
<0 : non-raining. | | Surface Flag | Integer SDS | 1 | npixel*nscan | - | 0 ~ 3 | - | Indicates the type of surface
0-ocean; 1-land; 2-coast; 3-other. | | Surface Rain | Float SDS | 4 | npixel*nscan | - | 0.0 ~ 3000.0 | mm/h | Instantaneous rain rate at the surface for each pixel. | | Convective Surface Rain | Float SDS | 4 | npixel*nscan | - | 0.0. ~ 3000.0 | mm/h | Instantaneous convective rain rate at the surface for each pixel. | | Confidence | Float SDS | 4 | npixel*nscan | - | 0.0 ~ 300.0 | K | Associated with the surface rain, and measured as an rms deviation in temperatures. | | Cloud Liquid Water | Integer SDS | 2 | nlayer*npixel*nscan | 1000 | 0.00 ~ 10.00 | g m-3 | Cloud liquid water content for each pixel at 14 layers. | | Precipitation Water | Integer SDS | 2 | nlayer*npixel*nscan | 1000 | 0.00 ~ 10.00 | g m-3 | Precipitation water content for each pixel at 14 layers. | | Cloud Ice Water | Integer SDS | 2 | nlayer*npixel*nscan | 1000 | 0.00 ~ 10.00 | g m-3 | Cloud ice water content for each pixel at 14 layers. | | Precipitation Ice | Integer SDS | 2 | nlayer*npixel*nscan | 1000 | 0.00 ~ 10.00 | g m-3 | Precipitation content for each pixel at 14 layers. | | Latent Heating | Integer SDS | 2 | nlevel*npixel*nscan | 10 | -256 ~ 256 | °C/hour | Latent heating release for each pixel at 14 levels. | | Note: | nlevel: the number of latent heating levels (14)
nlayer: the number of profiling layers (14) | TRMM 2A12 can be accessed and ordered from the Goddard DISC's TRMM Data Search and Order System at http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&project=TRMM&dataGroup=Orbital&dataset=2A12:%20Hydrometeor%20Profile%20%28TMI%29&version=006. Papers associated with the over-ocean latent heating algorithm: Olson, W. S., C. D. Kummerow, S. Yang, G. W. Petty, W.-K. Tao, T. L. Bell, S.
A. Braun, Y. Wang, S. E. Lang, D. E. Johnson and C. Chiu. 2006: Precipitation and latent heating distributions from satellite passive microwave radiometry. Part I: Improved method and uncertainties. J. Appl. Meteor. and Climatol., 45, 702-720. Yang, S., W. S. Olson, J.-J. Wang, T. L. Bell, E. A. Smith and C. D. Kummerow. 2006: Precipitation and latent heating distributions from satellite passive microwave radiometry. Part II: Evaluation of estimates using independent data.
J. Appl. Meteor. and Climatol., 45, 721-739.
Appendix | TRMM 2A12 Scan Time | | Name | Format | Description | | Year | 2-byte integer | 4-digit year, e.g., 1998 | | Month | 1-byte integer | The month of the Year | | Day of Month | 1-byte integer | The day of the Month | | Hour | 1-byte integer | The hour (UTC) of the Day | | Minute | 1-byte integer | The minute of the Hour | | Second | 1-byte integer | The second of the Minute | | Day of Year | 2-byte integer | The day of the Year |
| TRMM 2A12 Data Flag Specific Values | | Value | Description | | 0 | Good data quality | | -9 | Channel brightness temperature outside valid range | | -15 | The neighboring 5 x 5 pixel array is incomplete due to edge or bad data quality | | -21 | Surface type invalid | | -23 | Date time invalid | | -25 | Latitude or longitude invalid |
| 14 Vertical Profiling Layers | | Layer Index | Layer Height | | 1 | surface - 0.5 km | | 2 | 0.5 - 1.0 km | | 3 | 1.0 - 1.5 km | | 4 | 1.5 - 2.0 km | | 5 | 2.0 - 2.5 km | | 6 | 2.5 - 3.0 km | | 7 | 3.0 - 3.5 km | | 8 | 3.5 - 4.0 km | | 9 | 4.0 - 5.0 km | | 10 | 5.0 - 6.0 km | | 11 | 6.0 - 8.0 km | | 12 | 8.0 -10.0 km | | 13 | 10.0 -14.0 km | | 14 | 14.0 - 18.0 km | | | 14 Vertical Heating Levels | | Level Index | Level Height | | 1 | 0 km | | 2 | 1 km | | 3 | 2 km | | 4 | 3 km | | 5 | 4 km | | 6 | 5 km | | 7 | 6 km | | 8 | 7 km | | 9 | 8 km | | 10 | 9 km | | 11 | 10 km | | 12 | 12 km | | 13 | 14 km | | 14 | 16 km | | |
Atmos Composition
