 |
| Titel |
Assessing satellite-based precipitation estimates in the Southern Appalachian mountains using rain gauges and TRMM PR |
| VerfasserIn |
O. P. Prat, A. P. Barros |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7340
|
| Digitales Dokument |
URL |
| Erschienen |
In: Precipitation: Measurement, Climatology, Remote Sensing, and Modeling (EGU Session 2009) ; Nr. 25 (2010-06-08), S.143-153 |
| Datensatznummer |
250015749
|
| Publikation (Nr.) |
 copernicus.org/adgeo-25-143-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| A study was performed using the first full year of rain
gauge records from a newly deployed network in the Southern Appalachian
mountains. This is a region characterized by complex topography with
orographic rainfall enhancement up to 300% over small distances (<8 km).
Rain gauge observations were used to assess precipitation estimates
from the Precipitation Radar (PR) on board of the TRMM satellite,
specifically the TRMM PR 2A25 precipitation product. Results show
substantial differences between annual records and isolated events (e.g. tropical
storm Fay). An overall bias of −27% was found between TRMM PR
2A25 rain rate and rain gauge rain rates for the complete one year of study
(−59% for tropical storm Fay). Besides differences observed for
concurrent observations by the satellite and the rain gauges, a large number
of rainfall events is detected independently by either one of the observing
systems alone (rain gauges: 50% of events are missed by TRMM PR; TRMM PR:
20% of events are not detected by the rain gauges), especially for light
rainfall conditions (0.1–2mm/h) that account for more than 80% of all the
missed satellite events. An exploratory investigation using a microphysical
model along with TRMM reflectivity factors at selected heights was conducted
to determine the shape of the drop size distribution (DSD) that can be
applied to reduce the difference between TRMM estimates and rain gauge
observations. The results suggest that the critical DSD parameter is the
number concentration of very small drops. For tropical storm Fay an increase
of one order of magnitude in the number of small drops is apparently needed
to capture the observed rainfall rate regardless of the value of the
measured reflectivity. This is consistent with DSD observations that report
high concentrations of small and/or midsize drops in the case of tropical
storms. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|