FY 1997

An intercomparison of near-surface wind products over the ocean on monthly mean and longer time scales, 1985–1995

McDermott, D., D.E. Harrison, and N. Larkin

NOAA Tech. Memo. ERL PMEL-110, NTIS: PB97-180111, 163 pp (1997)

This study presents a comparison of near-surface winds from three global wind products on monthly mean and longer time scales. The three products are: U.S. Navy, European Centre for Medium-Range Weather Forecasts (ECMWF), and U.S. National Centers for Environmental Prediction (NCEP). Vector winds, wind speed, divergence, pseudo-stress, and curl of pseudo-stress are compared for the period of 1985-1995. There is good agreement between the products in the Northern Hemisphere extra-tropics. In the tropics, along the west coast of the Americas, and over poorly observed regions of the Southern Hemisphere, the agreement between products can be very limited, especially for derived quantities like divergence or curl of pseudo-stress. There are large differences in the divergence within the Pacific Intertropical Convergence Zone, and in zonal winds in the Southern Hemisphere westerlies. Climatologies of 1985-1995 compare much better than do anomalies, as expected. To assess whether modifications during this period to the data assimilation techniques and models used to generate the wind products resulted in better agreement between the products, the first and last 5 years are compared separately. The agreement between products during the last 5 years is improved in some areas, but is worse in others.