Variational assimilation of meteorological observations in the lower atmosphere: A tutorial on how it works

2000 ◽  
Vol 62 (12) ◽  
pp. 1057-1070 ◽  
Author(s):  
Thomas W. Schlatter
Keyword(s):  
Lower Atmosphere ◽  
Variational Assimilation ◽  
Meteorological Observations

scholarly journals Observations of Thermally-Driven Winds in a Small Valley during the 21 August 2017 Solar Eclipse

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 389 ◽  
Author(s):  
Ross T. Palomaki ◽  
Nevio Babić ◽  
Gert-Jan Duine ◽  
Michael van den Bossche ◽  
Stephan F. J. De Wekker
Keyword(s):  
Boundary Layer ◽  
Solar Eclipse ◽  
Thick Layer ◽  
Lower Atmosphere ◽  
Topographic Features ◽  
Blue Ridge Mountains ◽  
Thermally Driven ◽  
Meteorological Observations ◽  
Lidar Observations ◽  
Small Valley

On the afternoon of 21 August 2017, a partial solar eclipse occurred over the Blue Ridge Mountains in central Virginia, USA. High-resolution meteorological observations were made on the floor of a small valley to investigate the effect of eclipse-induced cooling on thermally-driven winds. Measurements taken both at the surface and in the lower atmosphere indicate cooling throughout much of the atmospheric boundary layer. Multiple surface weather stations observed wind rotations that occurred both during and after the eclipse, as wind direction shifted from upvalley to downvalley and back to upvalley. The direction of these rotations (clockwise vs. counterclockwise) varied between stations and was strongly influenced by the proximity of the stations to topographic features in the valley. Doppler lidar observations over the valley floor show a 300 m thick layer of downvalley winds that formed below a deeper layer of upvalley winds. Changes in boundary layer winds and structure during the solar eclipse are similar to changes during the morning and evening transitions. However, the subtle differences in the direction of wind rotations between diurnal- and eclipse-transition periods provided important new insights into the interaction between slope- and valley flows, incoming solar radiation, and topographic features.

scholarly journals MODEL OF ESTIMATION OF PARAMETERS OF THE LOWER ATMOSPHERE BASED ON SATELLITE IMAGES AND GROUND-BASED

2019 ◽  
Vol 4 (1) ◽  
pp. 44-51
Author(s):  
Anatoly Lezhenin ◽  
Tatyana Yaroslavtseva ◽  
Vladimir Raputa
Keyword(s):  
Boundary Layer ◽  
Satellite Images ◽  
Urban Air Pollution ◽  
Lower Atmosphere ◽  
Estimation Of Parameters ◽  
Industrial Plants ◽  
Method Of Calculation ◽  
Pollution Research ◽  
Meteorological Observations ◽  
Wind Profiles

A method of calculation of wind profiles and coefficients of vertical turbulent exchange in the lower atmosphere is presented. The method is based on meteorological observations and satellite images of smoke plumes from high altitude chimneys of industrial plants. The method is used in a model of estimation based on solutions of the equations of the Ekman's a boundary layer. An analysis of distribution of the smoke plume of a power plant is given for the city of Barnaul. The results of calculations of wind velocity components in the boundary layer of the atmosphere are presented. A possibility of using this approach for urban air pollution research is shown.

scholarly journals Topoclimatic Studies of a High Arctic Plateau Ice Cap

1987 ◽  
Vol 33 (114) ◽  
pp. 149-158 ◽  
Author(s):  
Raymond S. Bradley ◽  
Mark C. Serreze
Keyword(s):  
High Arctic ◽  
Cooling Effect ◽  
Lower Atmosphere ◽  
Net Radiation ◽  
Degree Days ◽  
Local Climate ◽  
Ice Cap ◽  
North Eastern ◽  
Low Levels ◽  
Meteorological Observations

AbstractMeteorological observations on and around a small, exposed plateau ice cap on north-eastern Ellesmere Island, N.W.T., Canada, were carried out in the northern summers of 1982 and 1983. The objective was to assess the effect of the ice cap on local climate as the melt season progressed. In 1982, seasonal net radiation totals were lowest on the ice cap and greatest at the site farthest from the ice cap. The ice-cap site received only 35% of net radiation totals on the surrounding tundra. This reflects a gradient in albedo; albedo changed most markedly away from the ice cap as the summer progressed. A thermal gradient was observed along a transect perpendicular to the ice-cap edge; this gradient was greatest at low levels (15 cm) and was maximized under cloud-free conditions. The “cooling effect” of the ice cap was less at the start of the ablation season than later. Low-level inversions occurred more frequently over the ice cap than over the snow-free tundra. Overall, melting degree days on the ice cap were only 40–65% of those on the adjacent tundra. A model of interactions between the atmosphere and a snow and ice cover, or a snow-free tundra/felsenmeer surface is proposed. Observations indicate that the ice cap has a cooling effect on the lower atmosphere relative to the adjacent snow-free tundra; this effect is absent when snow cover is extensive (as in 1983).

scholarly journals Topoclimatic Studies of a High Arctic Plateau Ice Cap

1987 ◽  
Vol 33 (114) ◽  
pp. 149-158
Author(s):  
Raymond S. Bradley ◽  
Mark C. Serreze
Keyword(s):  
High Arctic ◽  
Cooling Effect ◽  
Lower Atmosphere ◽  
Net Radiation ◽  
Degree Days ◽  
Local Climate ◽  
Ice Cap ◽  
North Eastern ◽  
Low Levels ◽  
Meteorological Observations

AbstractMeteorological observations on and around a small, exposed plateau ice cap on north-eastern Ellesmere Island, N.W.T., Canada, were carried out in the northern summers of 1982 and 1983. The objective was to assess the effect of the ice cap on local climate as the melt season progressed. In 1982, seasonal net radiation totals were lowest on the ice cap and greatest at the site farthest from the ice cap. The ice-cap site received only 35% of net radiation totals on the surrounding tundra. This reflects a gradient in albedo; albedo changed most markedly away from the ice cap as the summer progressed. A thermal gradient was observed along a transect perpendicular to the ice-cap edge; this gradient was greatest at low levels (15 cm) and was maximized under cloud-free conditions. The “cooling effect” of the ice cap was less at the start of the ablation season than later. Low-level inversions occurred more frequently over the ice cap than over the snow-free tundra. Overall, melting degree days on the ice cap were only 40–65% of those on the adjacent tundra. A model of interactions between the atmosphere and a snow and ice cover, or a snow-free tundra/felsenmeer surface is proposed. Observations indicate that the ice cap has a cooling effect on the lower atmosphere relative to the adjacent snow-free tundra; this effect is absent when snow cover is extensive (as in 1983).

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