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Subject
ECMWF hosted the GEWEX sponsored Workshop on Objective Analysis of
Precipitation from 11 to 13 March 2003.
Aim
The primary goals of the workshop are to improve our understanding of
the issues involved in the objective analysis of precipitation using the
many sources of information available (e.g., gauges, satellite-derived
estimates, radar observations and model output data) and to make recommendations
for GPCP to advance its efforts to provide global analyses of precipitation.
While the current GPCP precipitation analyses, as well as others that
have been constructed, have proven useful for many purposes, it has become
clear that efforts to improve their accuracy and consistency are required.
This is partly because of the desire for higher spatial and temporal resolution,
which necessitates extracting more information from the available data,
and partly because the methods currently in use were developed 5-10 years
ago and the state of the science has advanced. This workshop will bring
together members of the GPCP community with experts in the theory and
practice objective analysis, including in particular, members of the numerical
weather prediction (NWP) community, to describe the current state of the
science and to make recommendations to GPCP.
Some of the questions that will be considered at the workshop are:
- What is the best (in terms of efficiency, accuracy and physics) analysis
procedure for merging and interpolating (spatially and temporally) the
various precipitation estimates?
- Are different analysis procedures needed for different spatial and
temporal scales?
- What analysis procedures should be used in complex terrain?
- What is the best way to validate results of analyses? How does one
validate over the open ocean?
- Since objective analysis techniques deal best with unbiased input
data:
- How can biases in the various input data be removed?
- Are these biases function of satellite type, geographical location,
season and even observation time or date?
- Can they be done once for all or need to be done at every analysis
time, i.e., are they stationary or time dependent?
- Is bias removal best done during the retrieval process or during
the analysis of by a combination of both?
Presentations are planned for the first two days and the remainder is
reserved for discussion and preparation of workshop recommendations.
Timetable
Abstracts of presentations
Any request for information regarding this meeting should be directed
to the organizers: Masao Kanamitsu
or Arnold Gruber.
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