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Abstract. Two extratropical marine cyclones and their associated frontal features are examined by computing surface pressure fields from NASA scatterometer (NSCAT) winds. A variational method solves for a new surface pressure field by blending highresolution (25 km) relative vorticity computed along the satellite track with an initial geostrophic vorticity field. Employing this method with each successive pass of the satellite over the study area allows this surface pressure field to evolve as dictated by the relative vorticity patterns computed from NSCAT winds. The result is a high-resolution surface pressure field that captures features such as fronts and low-pressure centers in more detail than National Centers for Environmental Prediction (NCEP) reanalyses. While using the actual relative vorticity to adjust the geostrophic vorticity ignores the ageostrophy of surface winds, which can be significant in the vicinity of fronts and jet streaks, it is a necessary approximation given that the technique uses only surface data. The NSCAT surface pressure fields prove to be nearly as accurate as NCEP reanalyses when compared to ship and buoy observations, which is an encouraging result given that NCEP reanalyses incorporate a myriad of data sources and the NSCAT fields rely primarily on one source. In addition, the high-resolution relative vorticity fields computed from NSCAT winds reveal the location of surface fronts in great detail. These fronts are verified using NCEP analyses, in situ data, and satellite imagery.

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Historical weather data of the Southeast U.S.A. was divided into baseline (neutral, 1981-2000), warm (1935-1954) and cold (1958-1977) periods and used in impact simulation experiments to understand climate effects on a summer and a winter crop. Simulated summer crop (maize) yields were lower in the warm than the cold period, but also low during a neutral period. Simulated winter crop (wheat) yields were higher during the neutral period than during the warm and cold periods. A higher average temperature of a given period did not necessarily translate to lower crop yields. Specifically, the summer crop (maize) experienced about 7 % reduction in growing season length per degree increase in mean air temperature, and about 5 % for the winter (wheat) crop. Overall, the simulated maize yield was reduced by 13 % and wheat yield by 6.5 % per unit of increase temperature. In conclusion, simulated yield reduction per unit increase in mean temperature was reduced during the neutral period for the summer while for the winter crop there were fewer differences between the warm and neutral periods. The summer crop was sensitive to changes of mean growing season temperatures while the winter crops was sensitive to changes in CO 2 .

Recent predictions of increased hurricane activity in the Atlantic basin, as well as explosive coastal population growth, have prompted a study of the trends in quantity and intensity of U.S. landfalling hurricanes in the Gulf of Mexico. Gulf of Mexico hurricane landfalls from Cape Sable, Florida, to Brownsville, Texas, are binned by decade from 1886 to 1995 to determine whether gulf hurricane landfalls are becoming more or less frequent. From these bins, subsets of intense hurricanes (sustained winds of 96 kt or more) per decade are also made. The results show that there is no sign of an increase of hurricane frequency or intensity in the Gulf of Mexico at this time.