(Paper about diurnal cycles of cloud and precipitation)

rainfall estimates

Diurnal Cycles

Before the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite [Kummerow et al., 1998] in late 1997, most studies of the diurnal cycle of tropical convective clouds used infrared data only [e.g., Fu et al., 1990; Janowiak et al., 1994; Garreaud and Wallace, 1997]. A typical metric would be the area covered by clouds whose outgoing long wave radiation (or IR brightness temperature) was less than some specified value [e.g., Hall and Vonder Haar, 1999; Yang and Slingo, 2001]. The area covered by cold cloud was often used as a proxy for coverage of deep or intense convection, or for rainfall. The association is a logical one, because high cold clouds are usually anvil clouds produced directly by deep precipitating convective clouds.

Using the Precipitation Radar (PR), the Visible and Infrared Scanner (VIRS), and the Lightning Imaging Sensor (LIS) on the TRMM satellite, it is possible now to separate information on clouds, precipitation, and lightning, and to demonstrate the intensity of the precipitating convection, and do so globally [Nesbitt and Zipser, 2003; Cecil et al., 2005; Liu et al, 2007, Liu and Zipser, 2008]. Some of the diurnal cycle loops of precipitation, cloud and rainfall contribution from different types of precipitation systems (Precipitation Features, PFs) can be accessed below:

PFs Population fraction Rainfall contribution Diurnal loop
Size range 75-500 km^2 20.0% 13.5% diurnal
Size range 500-2000 km^2 2.5% 12.8% diurnal
Size range > 2000 km^2 1.0% 68.5% diurnal
Volumetric rainfall > 1000 mm/hr*km^2 4.3% 84.3% diurnal
Volumetric rainfall > 10000 mm/hr*km^2 0.7% 65.8% diurnal
Volumetric rainfall > 50000 mm/hr*km^2 0.2% 46.2% diurnal
No lightning 99.4% 74.8% diurnal
Flashrate 0-10 flash/minute 0.5% 16.8% diurnal
Flashrate > 10 flash/minute 0.1% 8.4% diurnal
Maximum height of 20 dBZ > 0 km 89.9% 99.9% diurnal
Maximum height of 20 dBZ > 5 km 16.7% 85.1% diurnal
Maximum height of 20 dBZ > 10 km 1.1% 43.3% diurnal
Maximum height of 40 dBZ > 0 km 4.5% 80.0% diurnal
Maximum height of 40 dBZ > 5 km 0.8% 37.8% diurnal
Maximum height of 40 dBZ > 10 km 0.0% 1.9% diurnal
Minimum 85 GHz PCT < 250 K 3.4% 75.0% diurnal
Minimum 85 GHz PCT < 200 K 0.7% 45.8% diurnal
Minimum 85 GHz PCT < 150 K 0.1% 17.7% diurnal
Minimum infrared TB < 210 K 2.7% 45.2% diurnal
Minimum infrared TB < 235 K 15.1% 76.4% diurnal

Occurrenc of cloud and precipitation at altitudes

Occurrence of cloud with VIRS infrared TB < 210 K diurnal loop
Occurrence of cloud with VIRS infrared TB < 235 K diurnal loop
Occurrence of cloud with VIRS infrared TB < 273 K diurnal loop
Occurrence of 20 dBZ at 02 km diurnal loop
Occurrence of 20 dBZ at 04 km diurnal loop
Occurrence of 20 dBZ at 06 km diurnal loop
Occurrence of 20 dBZ at 08 km diurnal loop
Occurrence of 20 dBZ at 10 km diurnal loop
Occurrence of 20 dBZ at 12 km diurnal loop
Occurrence of 20 dBZ at 14 km diurnal loop

 

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