scholarly journals Dominant Regimes of the Ross Ice Shelf Surface Wind Field during Austral Autumn 2005

2007 ◽  
Vol 46 (11) ◽  
pp. 1933-1955 ◽  
Author(s):  
Mark W. Seefeldt ◽  
John J. Cassano ◽  
Thomas R. Parish
Keyword(s):  
Wind Field ◽  
Surface Wind ◽  
Wind Regime ◽  
Ice Shelf ◽  
Sea Level Pressure ◽  
Ross Ice Shelf ◽  
Pressure Fields ◽  
Wind Regimes ◽  
Surface Wind Field ◽  
Austral Autumn

Abstract An analysis of the surface wind field across the Ross Ice Shelf, Antarctica, is conducted for austral autumn 2005. The airflow is divided into dominant wind regimes identifying similar wind patterns and the associated typical atmospheric forcing. The results of previous research and a seasonal analysis of the recently expanded network of automatic weather stations in the Ross Ice Shelf region are used to define the dominant wind regimes. Events composing each wind regime are identified by matching wind speed and wind direction observations at several automatic weather station sites for durations of at least 10 h. The four different dominant wind regimes are barrier wind, strong katabatic, weak katabatic, and light wind. Each wind regime is studied through the use of wind rose plots and sea level pressure fields from the Antarctic Mesoscale Prediction System. The sea level pressure fields are used to characterize the forcing of the surface wind field by synoptic pressure gradients. The four dominant wind regimes result in classifying less than 50% of the total hours for austral autumn 2005. The results indicate that previous studies of the Ross Ice Shelf surface wind field, focusing on katabatic winds and barrier winds, represent less than one-half of the observed winds. This study provides a better understanding of the composition of the surface wind field in Antarctica and more insight into the characteristics of the Ross Ice Shelf airstream.

scholarly journals Winter Wind Regimes over Israel Using Self-Organizing Maps

2017 ◽  
Vol 56 (10) ◽  
pp. 2671-2691 ◽  
Author(s):  
Sigalit Berkovic
Keyword(s):  
Surface Wind ◽  
Pressure Gradients ◽  
Wind Regime ◽  
Self Organizing Maps ◽  
Diurnal Variability ◽  
Easterly Wind ◽  
Synoptic Classification ◽  
Wind Measurements ◽  
Wind Regimes ◽  
Self Organizing

AbstractThe aim of this study is to objectively define and automatically reconstruct surface wind regimes over Israel. Unlike other previous studies that subjectively examined case studies or applied the semiobjective synoptic classification (SOC), this study shows the ability of the method of self-organizing maps (SOM) to directly define well-known wind regimes at the synoptic hours (0000, 0600, 1200, and 1800 UTC) during the winter. This ability sets the groundwork for future automatic climatological analysis and applications. The investigation is performed by analyzing surface wind measurements from 53 Israel Meteorological Service stations. The relation between the synoptic variables and the wind regimes is revealed from the averages of ECMWF interim reanalysis (ERA-Interim) variables at each SOM wind regime. The inspection of wind regimes and their average pressure anomalies has shown that wind regimes relate to the gradient of the pressure anomalies rather than to the specific isobaric pattern. Two main wind regimes—strong western and strong eastern—are well known over this region. During daytime, SOM classification identifies these two regimes while SOC reveals only strong western regimes since SOC considers depth of the pressure gradients only in the case of low pressure centers. In accordance with previous studies, two main groups—winter low and high pressure centers and/or Red Sea troughs—are related to the strong westerly or easterly wind regimes with low diurnal variability and high daily persistence. Regimes under weak pressure gradients have higher diurnal variability, relatively lower steadiness, and weaker speed. Their daily persistence is not necessarily low.

The Effects of Vertical Stratification and Land Use Data on Numerical Simulation of Wind Energy Resources

2014 ◽  
Vol 535 ◽  
pp. 135-140
Author(s):  
Yuan Chang Deng ◽  
Zhen Cao Zou
Keyword(s):  
Numerical Simulation ◽  
Land Use ◽  
Wind Field ◽  
Wind Profile ◽  
Surface Wind ◽  
Wrf Model ◽  
Vertical Stratification ◽  
Near Surface ◽  
Wind Field Simulation ◽  
Surface Wind Field

By adjusting the distribution of vertical layers and increasing its number in WRF model, this paper mainly studies the effects of vertical stratification on the near surface wind field and vertical profile simulation. The test outcomes show that moderately increasing vertical layers can effectively improve the near surface wind field simulation results, while it has little influence on the numeral and changing trend of high vertical wind profile. Considering both accuracy and efficiency, it is recommended to set 10~15 layers below 300m. On the basis of this research, instead of USGS data by using the MODIS_30S data, the data underlying surface land in Shenzhen and HK area are updated. Comparative results between the two schemes, due to the roughness and drag coefficient of difference types of surface are not identical; the surface data has a significant impact on wind field and wind profile simulation. Using the MODIS land use data which is more consistent with the actual situation can improve the accuracy of numerical simulation.

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