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One decade of TRMM data enough to show the trend of the climate change?

20dbz

Observations of the precipitation and the population of the storms during the past decade would certainly help us understanding the climate change. However, we have to be cautious on how to interpret the long term satellite observations. The calibration of satellite data has always been a challenge, such as instrument sensitivity degradation etc. For TRMM observations, this becomes more complicated because there was a satellite orbit change from 350 km to 402 km in August 2001 to extend the life time of the observation. The orbit change leads to different instrument geometries and sensitivities (DeMoss and Nowman 2007; Shimizu et al. 2009; Short and Nakamura 2010). Besides the orbit boost, the diurnal sampling is an other issue that has to be taken into account when interpreting the long term trend in the TRMM observations (Negri et al 2002).

Here we present the monthly variation of the population and rainfall contribution from Precipitation Features (defined from TRMM PR near surface rainfall) with different size and intensities. However, these results needs to be interpreted cautiously with the background of the TRMM satellite boost and instrument sensitivity changes. .

Time series of population and rainfall contribution of PFs with different sizes and intensities


PFsPopulation fractionRainfall contribution
Size range 75-500 km^2 20.30% see picture 13.47% see picture download data
Size range 500-2000 km^2 2.54% see picture 12.81% see picture download data
Size range > 2000 km^2 0.99% see picture 70.04% see picture download data
Volumetric rainfall > 1000 mm/hr*km^2 4.35% see picture 85.87% see picture download data
Volumetric rainfall > 10000 mm/hr*km^2 0.69% see picture 67.31% see picture download data
Volumetric rainfall > 50000 mm/hr*km^2 0.19% see picture 47.63% see picture download data
No lightning 99.39% see picture 74.85% see picture download data
Flashrate 0-10 flash/minute 0.53% see picture 17.00% see picture download data
Flashrate > 10 flash/minute 0.08% see picture 8.57% see picture download data
Maximum height of 20 dBZ > 0 km 89.94% see picture 99.98% see picture download data
Maximum height of 20 dBZ > 5 km 16.75% see picture 86.53% see picture download data
Maximum height of 20 dBZ > 10 km 1.13% see picture 44.29% see picture download data
Maximum height of 40 dBZ > 0 km 4.46% see picture 81.42% see picture download data
Maximum height of 40 dBZ > 5 km 0.79% see picture 38.71% see picture download data
Maximum height of 40 dBZ > 10 km 0.04% see picture 1.98% see picture download data
Minimum 85 GHz PCT < 250 K 3.34% see picture 74.76% see picture download data
Minimum 85 GHz PCT < 200 K 0.66% see picture 45.69% see picture download data
Minimum 85 GHz PCT < 150 K 0.15% see picture 17.70% see picture download data
Minimum infrared TB < 210 K 2.62% see picture 45.36% see picture download data
Minimum infrared TB < 235 K 14.84% see picture 76.40% see picture download data
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