Global Satellites Mapping of Precipitation Project in Japan(GSMaP)- Microwave and Infrared combined algorithm -
K. Okamoto, T. Ushio, T. Iguchi, N. Takahashi…...../ Tomoo Ushio (Osaka Prefecture University)
Algorithm inputs
Microwave RadiometersTRMM/TMI from JAXAAqua/AMSR-E from JAXA (not included yet)
Infrared RadiometersGlobal Merged Geo-IR from TSDIS
What, When, Where, and How do we analyze for?
Purpose: To draw the global precipitation map with 0.1 degree/1 hour resolution
What: 1hour global IR data from Goddard/DAAC and TMI/2A12 data
When:August 1 to 10, 2000 Where: -35 to 35 in latitude, 0 to 360 in longitude How: By interpolating precipitation between TMI
overpasses using the cloud motion inferred from 1 hour IR Tb.
11.4 μm Geo IR1 hour before
10.8 μm Geo IRPresent
11.4 μm Geo IRPresent
Infrared (IR) Data
Microwave Radiometer (MWR) Data
1 hr Moving Vector
GSMaP Data
Split Window
GSMaPPresent
GSMaP1 hour before
1 hr MWRPresent
Algorithm outflow
Predicted GSMaP
Typhoon JELAWAT
地域 : 太平洋北部
TRMM観測数 : 12
Correlation between radar and the GSMaP product Correlation between radar and the GSMaP product as a function of the past microwave satellite as a function of the past microwave satellite overpassoverpass
0
0.10.2
0.30.4
0.5
0.60.7
0.8
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14Time (hour)
Corre
lation
coeffi
cient
Strength and weakness of underlying assumptions Strength
We mainly use the MWR data which is proved to be excellent for rainfall estimation.
Fast processing time (About 3 min.) for the real time operations Weakness
Physically simple. (We do not think any phase change or so.) Only TRMM/TMI is used. Not use the backward process, resulting in large error. Moving vector is not validated at all. Any validations have not yet being done at all.
Planned modifications/ Improvements Current to short term
Introduce AMSR-E in addition to TRMM/TMI by the Aonashi algorithm
Apply the Kalman filtering technique to adjust the interpolated precipitation rate between the microwave passes.
Long term Apply the split window method by Inoue (1999) Introduce SSM/I (F13, 14, 15) Validation through the comparison with the radar-rain gauge
network in Japan Cross comparison with another precipitation map Input to the global circulation model.
Algorithm output information Spatial resolution 0.1 degree Spatial coverage
-35 to 35 in latitude (TMI only) -60 to 60 in latitude (TMI + AMSR-E)
Update frequency 1 hour Date latency
Our product is just made, and it is not operational now. Source of real time data/ Source of archive data
Microwave Radiometers TRMM/TMI from JAXA Aqua/AMSR-E from JAXA
Infrared Radiometers Global Merged Geo-IR from TSDIS
Capability of producing retrospective data (data and resources required/ available) Currently we would go back to the 1998 (TRMM era)
Radar rain gauge analysis in Japan
Current StatusBeth gave us the IDL code to process.My student, Mr. Yasuhida Iida, read the code
and made some small modification.He could successfully draw the map for
intercomparison.