Large Sample Basin Experiments for Hydrological Model Parameterization: Results of the Model Parameter Experiment–MOPEX. IAHS Publ. 307, 2006, 9–28.
The US MOPEX Data Set
JOHN SCHAAKE1, SHUZHENG CONG1 & QINGYUN DUAN2
1 Office of Hydrologic Development, NOAA National Weather Service, 1325 East–West Avenue, Silver Spring, Maryland 20910, USA
john.schaake@noaa.gov
2 Lawrence Livermore National Laboratory, Energy and Environment Directorate, 7000 East Avenue, Livermore, California 94550, USA
Abstract A
key step in applying land surface parameterization schemes is to estimate model
parameters that vary spatially and are unique to each computational element.
Improved methods for parameter estimation (especially for parameters important
to runoff response) are needed and require data from a wide range of climate regimes throughout the world. Accordingly, the
GEWEX Hydrometeorology Panel (GHP) endorsed the concept of an
international Model Parameter Estimation Project (MOPEX) at its Toronto
meeting, August 1996. Phase I of MOPEX was funded by NOAA in financial year
(FY) 1997, Phase II in FY 2000 and Phase III in FY 2003. MOPEX was adopted as a
project of the IAHS/WMO Working Group on GEWEX and of the WMO Commission on
Hydrology (CHy), and is now a contributor to the Combined Enhanced Observing
Period (CEOP) of the World Climate Research Program (WCRP). In 2004, MOPEX
became a Working Group of the IAHS Prediction in Ungauged Basins (PUB)
Initiative. MOPEX is also expected to contribute to the work of the Hydrologic
Ensemble Prediction Experiment (HEPEX). The primary goal of MOPEX is to develop
techniques for the a priori estimation of the parameters used in land
surface parameterization schemes of atmospheric models and in hydrological
models. A major early effort of MOPEX has been to assemble a large number of
high-quality historical hydrometeorological and river basin characteristics
data sets for a wide range of river basins (500–10000 km2)
throughout the world. MOPEX data sets are available via the Internet (ftp://hydrology.nws.noaa.gov/pub/gcip/mopex/US_Data/).
This paper documents the development of data sets for river basins in the USA.
Several highly successful parameter estimation workshops have been organized
by MOPEX. The first was held as part of the IAHS General Assembly in
Birmingham, UK, in July 1999. The second workshop was hosted in April 2002 in
Tucson, Arizona, USA, by the SAHRA/University of Arizona. The third MOPEX
workshop was held as part of the IAHS General Assembly in Sapporo, Japan, July
2003. The fourth, in Paris, France, July 2005 was organized by the CEMAGREF in
collaboration with the ENGREF, Météo France, National Weather Service and the
SAHRA/University of Arizona. The fifth workshop was held as part of the IAHS
Scientific Assembly, February 2005, Foz do
Iguacu, Brazil. The purpose of the future phases of the project is to: (a)
continue collecting additional international data sets; update data from the
USA by adding recent years, including data for elevation zones in mountainous
areas and refining energy forcing data; (b) continue to conduct international
MOPEX workshops; (c) provide leadership to develop a better scientific understanding
of how to improve procedures for a priori
parameter estimation; (d) make a significant hydrological contribution to CEOP
and PUB; and (e) demonstrate transferability of MOPEX results. The basic data
collection strategy being used in MOPEX is to seek the most readily available
and highest quality data first. During the next three years, analyses of the
available MOPEX data sets by the international scientific community will be
emphasized.
Key words a priori; calibration; hydrological models;
parameters; regionalization; transferability; uncertainty