FTIPP

FCLIM / TRMM / IRP Precipitation Pentads

aboaf(A bit of Acronym Forensics)

FCLIM

FEWS Net Climatology

Famine Early Warning Systems Network

TRMM Tropical Rainfall Measuring Mission

3B42 V6, RTThe combined instrument rain calibration algorithm (3B-42) uses an

optimal combination of 2B-31, 2A-12, SSMI, AMSR and AMSU precipitation estimates (referred to as HQ), to adjust IR estimates from geostationary IR observations. Near-global estimates are made by calibrating the IR brightness temperatures to the HQ estimates. The 3B-42 estimates are scaled to match the monthly rain gauge analyses

used in 3B-43.

0.25 Deg 3-hourly 50N - 50S 1998-today

IRCPC IR Brightness Temperatures

The Climate Prediction Center/NCEP/NWS is now making available globally-merged (60N-60S) pixel-resolution IR brightness temperature data (equivalent blackbody temps), merged from all available geostationary satellites (GOES-8/10, METEOSAT-7/5 & GMS). The availability of data from METEOSAT-5, which is located at 63E at the present time, yields a unique opportunity for total global (60N-60S) coverage.

4km 1/2-hourly 60N - 60S 2000-today

IRP - IR derived Precipitation

Basic idea,

IR ~ Temperature

Cold ~ Clouds

Clouds ~ Precip

So,

IR ~ Precip

IRP in the W. Hemisphere

For each 1/4 degree pixel

and pentad (1-72)

for given month (2001-2009)

for given threshold (260-300K)

regress (TRMM daily rain rate) onto (%IR below TH)

Find the TH with the best correlation,

that becomes your model for that point

Apply this to .05 degree IR data to get .05 deg IRP

FTIPP Calculations

FTIPP = FCLIM * (%TRMM + %IRP)/2

%TRMM = (TRMM.data + ) / (TRMM.clim + )%IRP = (IRP.data + ) / (IRP.clim + )

Other things…• Converting monthly FCLIM to pentads• How to use TRMM-RT before V6 available• How to validate• De-artifacting• From development to operational• Improve FTIPP using station data• FTIPP on other continents• Get into EWX