Synoptic Climatology for the Susquehanna River Basin
Objectives
SRBEX research in synoptic climatology has three current foci:
- Determining representative circulation patterns and their hydrologic
response;
- Establishing empirical relationships between the response of watersheds
with differing scales and synoptic forcing;
- Developing techniques to monitor large-scale climatic variation.
Current Activities
The first focus arises from the assumption by the SRBEX linked-modeling efforts that there is a strong
causal relationship between the atmospheric circulation and the
hydrologic response of the basin. Many of the simulations linking the
atmosphere and basin hydrology rely on observed events believed to be
typical. Yet no methodology has been developed to determine either the
representativeness of the circulation patterns producing a significant
hydrologic response, or the representativeness of the hydrologic
response to a given storm system. In preliminary research, Yarnal and
Draves (1993) used
composite pressure patterns and storm tracks to show that the largest
runoff events in the Susquehanna River Basin (SRB) may result from
characteristic sequences of synoptic patterns. Consequently, Frakes and
Yarnal (1994) have developed
a technique for determining unique circulation events and those storm
patterns that typically produce a strong hydrologic response in the
basin. These data can also be used to understand which hydrologic
responses to a given circulation event are representative or not. The
results suggest that synoptic climatology is a useful tool for defining
model scenarios and model verification in global-change experiments.
SRBEX also seeks to identify how watersheds of differing scales respond
to forcing by weather systems. The second focus of SRBEX synoptic
climatology addresses the observational component of this objective.
Frakes and Yarnal (1995) are creating a
catalog of daily eigenvector-based synoptic map patterns, plus indices
based on these patterns (Yarnal,
1993) for the period 1946-1994. Quarterly updates of the catalog
will be available in hard copy and over the Internet starting in the
last quarter of 1995. These data will be integral to developing
long-range forecasts of basin climate and hydrology.
Results
Last change: 3 May 1995,
R. A. White / raw@essc.psu.edu