Level Surface Wind Research Articles

Comments on “a synoptic climatological analysis of air quality in the Grand Canyon National Park”

Comments on “a synoptic climatological analysis of air quality in the Grand Canyon National Park”

The relationship of hurricane reconnaissance flight-level wind measurements to winds measured by NOAA's Oceanic platforms

A well-known problem in hurricane forecasting and in the administration of hazardous weather warnings and advisories concerns what adjustment to make to flight-level reconnaissance wind observations in order to make them representative of sustained surface winds. To solve this problem, a study was initiated comparing NOAA reconnaissance flight-level winds to 10 m level observations from NOAA's oceanic buoys and platforms. A data base was created that consisted of comparisons made whenever the aircraft observation was: (1) within 10 km radial seperation from the surface platform (in a storm-relative coordinate system), (2) within ±4 h of the surface observation time, (3) within ±2 h of the surface observation time. The data base contains all storms flown by NOAA aircraft in the vicinity of the Atlantic and Gulf of Mexico buoy network over the eleven year period from 1975–1986. Comparisons from these criteria are discussed in terms of the ratio of the buoy-measured wind speed (VB) to the aircraft measured wind speed VA. Results indicate that the 10 m level surface winds over water were within 55–85% of the winds measured by the reconnaissance aircraft. The ratio VB/VA depended strongly on the low-level atmospheric stability as indicated by the buoy air-sea temperature difference.

The relationship of hurricane reconnaissance flight-level wind measurements to winds measured by NOAA's oceanic platforms

A well-known problem in hurricane forecasting and in the administration of hazardous weather warnings and advisories concerns what adjustment to make to flight-level reconnaissance wind observations in order to make them representative of sustained surface winds. To solve this problem, a study was initiated comparing NOAA reconnaissance flight-level winds to 10 m level observations from NOAA's oceanic buoys and platforms. A data base was created that consisted of comparisons made whenever the aircraft observation was: (1) within 10 km radial seperation from the surface platform (in a storm-relative coordinate system), (2) within ±4 h of the surface observation time, (3) within ±2 h of the surface observation time. The data base contains all storms flown by NOAA aircraft in the vicinity of the Atlantic and Gulf of Mexico buoy network over the eleven year period from 1975–1986.Comparisons from these criteria are discussed in terms of the ratio of the buoy-measured wind speed (VB) to the aircraft measured wind speed VA. Results indicate that the 10 m level surface winds over water were within 55–85% of the winds measured by the reconnaissance aircraft. The ratio VB/VA depended strongly on the low-level atmospheric stability as indicated by the buoy air-sea temperature difference.

Long-Range Transport of Air Pollution under Light Gradient Wind Conditions

The long-range transport of air pollution on clew days under light gradient wind conditions is investigated from an analysis of all days with high oxidant concentrations in 1979 at locations in central Japan that are far from pollutant sources. Surface-level wind and pressure distributions over a 300×300 km area were analyzed, together with concentration isopleths of oxidants and suspended particles produced by photochemical reactions. It was found that the transport mechanism consists of. 1) land/sea breezes; 2) a steady onshore wind driven by the diurnal-mean land–sea temperature difference; 3) the generation of a strong thermal low in the inland mountainous region in the daytime; and 4) a subsidence inversion accompanied by a synoptic-scale high pressure system. The last three mechanisms work to combine land/sea breezes and slope and valley winds into one large-scale high-speed wind field that transports pollutants a long distance inland into the mountainous region.