The hydroclimatology of the United States during El Nino/Southern Oscillation

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:398259

Dracup, J A; Piechota, T C; Khachikian, C S ^[1]

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1. Univ. of California, Los Angeles, CA (United States). Civil and Environmental Engineering Dept.

Palmer Drought Severity Index (PDSI) monthly data are analyzed, building on a previous study that investigated the influence of the El Nino/Southern Oscillation (ENSO) on US streamflow. Harmonic analysis is performed using data from 1,035 selected climatological stations, allowing observation of the biennial tendency in climate data. With the middle twelve months defined as the El Nino year (0), an idealized first harmonic fit to a 24-month ENSO composite is computed for each station. By plotting the first harmonic vectors of each station, regions of similar, or coherent, response are identified. The regions identified using PDSI data represent wet conditions in the Gulf of Mexico (Gm1 and GM2) and central (C) US, and dry conditions in the Pacific northwest (PNW) and northeast (NE) US. The PNW region exhibits the strongest interrelationship between ENSO and extreme drought events. Comparing PDSI data results with other hydroclimatic data (temperature, precipitation, and streamflow) reveals consistent responses. The most filtered response is seen in the PDSI and streamflow data, and these data are probably the best measure of the overall hydroclimatic response within a region. Results of this study suggest that conditions in the tropical Pacific (e.g., sea surface temperatures) may be excellent precursors of future climate. These conditions may also enhance long range prediction of droughts and floods for certain regions of the US.

• OSTI ID: 398259
• Report Number(s): CONF-950666--; ISBN 1-882132-33-5
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AMBIENT TEMPERATURE
ATMOSPHERIC PRECIPITATIONS
CLIMATIC CHANGE
DROUGHTS
ENVIRONMENTAL EFFECTS
FORECASTING
PACIFIC OCEAN
SOUTHERN OSCILLATION