Global Precipitation Monitoring - Satellite-based Applications on Climate Change - page 88

CMORPH Precipitation Estimates

50N
40N
30N
20N
10N
EQ
10S
20S
30S
40S
50S

60E 120E 180 120W 60W 0

1 5 10 15 20 25 30 50 75 100 125 150

Fig. 6.5 CMORPH rainfall estimate (mm per day) for 2 June 2010

Although not truly global, these products have found a wealth of users in the
weather forecasting, climate monitoring, and hydrological communities. Typically,
they cover the geographic domain of 60ºS to 60ºN, have 3-h temporal sampling, and
are at 0.25 spatial resolution. Commonly referred to as high-resolution precipita-
tion products (HRPPs), they use the high spatial and temporal resolution of IR data
to resolve deficiencies in resolution of the higher quality PMW data, although there
are substantial differences between the exact methodologies employed. The HRPPs
can be categorized into two broad types: adjustment-based techniques where IR
data is calibrated using PMW estimates (where the two are often then combined)
and motion-based techniques, where the IR data is used to interpolate between
successive PMW overpasses.
The Pilot Evaluation of High-Resolution Precipitation Products (PEHRPP;
Sapiano and Arkin 2009 ) was established to intercompare and validate these
datasets. PEHRPP included a number of high-resolution datasets: the TRMM
Multi-satellite Precipitation Analysis (TMPA; Huffman et al. 2007 ), the CPC
Morphing technique (CMORPH; Joyce et al. 2004 ), the Hydro-Estimator (Scofield
and Kuligowski 2003 ), the NRL-Blended technique (NRL-Blended; Turk and
Miller 2005 ), Precipitation Estimation from Remotely Sensed Information using
Artificial Neural Networks (PERSIANN; Hsu et al. 1997 ; Sorooshian et al. 2000 ),
and the Global Satellite Mapping of Precipitation (GSMaP) project (Aonashi et al.
2009 ). CMORPH is the only motion-based technique out of these six. Figure 6.5
presents an example of the CMORPH product.

6.4 Summary and Future

There are various techniques to retrieve rainfall from satellites, each with their own
set of attributes that are dictated by the particular needs for the information. For
short-term, high spatial resolution applications like flash flood forecasting, the IR