Showing papers on "Weather station published in 1991"

Simulation of daily precipitation in the Pacific Northwest using a weather classification scheme

Abstract: A weather classification scheme was coupled with a semi-Markov model to represent the coincident occurrence of rain/no rain states at a single rain gauge and classes representing regional atmospheric circulation patterns, as identified from National Meteorological Center gridded observations for a large area of the North Pacific. Weather classes were identified from daily observations of surface pressure and 850 mb pressure height at five selected ten degree latitude by ten degree longitude cells using a K-means clustering algorithm, which was applied on a month-by-month basis. The number of climate classes, K, for each month was chosen based on a preliminary analysis of the model’s ability to describe statistics of observed precipitation occurrences at the Stampede Pass, Washington weather station. The length of stay distributions within each precipitation occurrence/weather class were assumed to be geometric, and the precipitation amounts for each class and season were fitted with a mixed exponential distribution. Parameters of the length of stay distributions, transition probabilities, and precipitation amounts were estimated from the period of record 1975–84.

July temperatures in kashmir and ladakh, india: comparisons of observations and general circulation model simulations

Abstract: The Himalayan mountain region represents a challenging laboratory to refine general circulation model simulations and to compare them with climate observations at regional and local geographical scales. This paper includes an analysis of July tem- peratures in the Great Himalaya Range of northern India. Five sources of data are analyzed: (1) coarse-scale model simulations for present climate (1 x CO2 runs), (2) regression model predictions of temperature versus elevation (after Lambert and Chitrakar, 1989), (3) spatially-interpolated observed data for the region (after Legates and Willmott, 1990), (4) individual station records in the region, and (5) local-scale field data taken in summer, 1988. As expected, July temperature simulations from general circulation models tend to generalize temperature/elevation relationships and do not appear to account for landscape surface feedbacks on air temperatures at a regional and local scale. Cautious use of climate model predictions of temperature and moisture for climate change scenario analyses is strongly encouraged. For mountain areas, field verification and weather station analyses for regional and local scales are essential for interpreting results from general circulation models.

Weather sensor arrangement esp. for deriving road traffic conditions - has common evacuation unit with membrane divided into regions associated with wind precipitation and auxiliary sensors

Abstract: A weather sensing arrangement contains precipitation, wind and fog sensors pref. with a common evaluation unit in one piece of equipment. The precipitation sensor has an upward facing membrane connected to a sensor element and detects a load on the membrane. The water deflected membrane (33), which can be heated, is divided into several regions. Each region is pref. connected to a sensor element (71, 72), e.g. a piezoceramic sensor. USE/ADVANTAGE - Compact, economical in use of materials and easy to mfr. Ascertains actual weather conditions at various locations for registration at weather station and display, e.g. on roadway warning shield.

Estimating crop top microclimates from weather station data

Abstract: A mathematical model (Microsim) was developed to estimate the microclimate at the top of nearby crops using inputs of weather station data and some knowledge about crop characteristics, such as height, albedo, and leaf area index. The model was tested using data measured simultaneously over a weather station and over each of two crops ‐ corn and soybean. Temperatures at the top of unstressed, uniform crops on level terrain within 1600 m of a recording weather station were estimated within 1.0° C 96% of the time for a corn crop and 92% of the time for a soybean crop. Winds at crop top were estimated within 0.4 m s−1 92% of the time for corn and 100% of the time for soybean. Energy balance flux density estimates for the corn crop resulted in correlation coefficients of r > 0.89 for each of Rn, LE, H and G. microsim worked well under atmospheric conditions that ranged from very stable to unstable. An enhancement was made to the model to describe wind and temperature profiles based on the complete fe...