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TRMM Microwave Imager (TMI) Level 3 Monthly 5° x 5° Oceanic Rainfall (3A11)

Data Access for

3A11: http://disc.sci.gsfc.nasa.gov/data/datapool/TRMM_DP/01_Data_Products/02_Gridded/01_Monthly_Tmi_Prod_3A_11/

Contents:

Summary

This document provides basic information on 3A11, TMI Monthly 5° x 5° Oceanic Rainfall Product. Algorithm 3A11 estimates monthly rain from the histogram of the brightness temperatures obtained from TMI calibration (1B11). This histogram is matched to a log-normally distributed rain rate distribution via a rain rate-brightness temperature relation. A beam-filling correction is applied to account for the non-uniformly filled field-of-view of the TMI sensor. Outputs are monthly surface rain rates and freezing heights for 5° x 5° grid boxes.

Data Flow Description

TMI Level 1A ==> 1B11 Calibrated TMI brightness temperatures ==> 3A11 TMI Monthly Oceanic Rainfall

The data flow of all products are shown in Satellite Algorithm Flow Diagram.

Data Set Description

Data Characteristics

Temporal Coverage Start Date: 1998-01-01; Stop Date: -
Geographic Coverage Latitude: 40°S - 40°N; Longitude:180°W - 180°E
Temporal Resolution Monthly
Horizontal Resolution 5° x 5°; nlat = 16, nlon = 72
Average File Size Compressed: ~23 KB; Original: ~53 KB
File Type HDF


Data Format Structure

The following table summarizes the contents and structure of the TMI monthly oceanic rainfall (3A11) product. Further information can be found in Volume 4 of the "File Specifications for TSDIS Products - Level 2 and Level 3" .
Data Format Structure for 3A11, TMI Monthly Oceanic Rainfall
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
GridStructure Char Attribute 5,000  - - - - GridStructure gives the specification of the geometry of the grids.
Monthly Rainfall Integer SDS 2  nlat*nlon 10 0.0 ~ 3000.0 mm The Monthly Rainfall is the surface rainfall over oceans in 5° x 5° boxes from 40°N x 40°S.
Number of Samples Integer SDS 4  nlat*nlon - 0 ~ 500,000 - The Number of Samples is that over oceans in 5° x 5° boxes for one month.
Chi Square Fit Integer SDS 4  nlat*nlon - 1 ~ 1,000,000,000 - The Chi Square Fit indicates how well the histogram of brightness temperatures fits the lognormal distribution function in 5° x 5° boxes for one month.
Freezing Level Integer SDS 2  nlat*nlon 100 0.00 ~ 6.00 km The Freezing Level is the estimated height of 0°C isotherm over oceans in 5° x 5° boxes for one month.
T_0 Integer SDS 2  nlat*nlon 10 160.0 ~ 180.0 oK The T_0 is the mean of non-raining brightness temperatures over oceans in 5° x 5° boxes for one month.
r_0 Integer SDS 2  nlat*nlon 100 0.00 ~ 15.00 mm
h-1		 The r_0 is the logarithmic mean rain rate over oceans in 5° x 5° boxes for one month.
Sigma_r Integer SDS 2  nlat*nlon 100 0.00 ~ 1.00 mm
h-1		 The Sigma_r(sr) is the standard deviation of logarithmic rain rates over oceans in 5° x 5° boxes for one month.
Probability of Rain Integer SDS 2  nlat*nlon 1000 0.000 ~ 1.000 - The Probability of Rain is that over oceans in 5° x 5° boxes for one month.
Quality Indicator 1 Integer SDS 2  nlat*nlon - - - TBD.
Quality Indicator 2 Integer SDS 2  nlat*nlon - - - TBD.
Quality Indicator 3 Integer SDS 2  nlat*nlon - - - TBD.
Spare Integer SDS 2  nlat*nlon - - - TBD.
Note for all SDS: Data on land areas are assigned the value -9999.
TRMM 3A11 can be accessed and ordered from the Goddard DAAC's TRMM Data Search and Order System at http://disc.sci.gsfc.nasa.gov/data/datapool/TRMM_DP/01_Data_Products/02_Gridded/01_Monthly_Tmi_Prod_3A_11/ .

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  • Last updated: Sep 18, 2009 10:32 AM ET