scholarly journals Recent trends and variations in surface meteorological parameters over Indian Antarctic station Maitri

MAUSAM ◽  
2021 ◽  
Vol 62 (4) ◽  
pp. 547-556
Author(s):  
O.P. SINGH ◽  
U.P. SINGH ◽  
R.P. LAL
Keyword(s):  
Surface Pressure ◽  
Meteorological Parameters ◽  
Meteorological Data ◽  
Surface Wind ◽  
Negative Temperature ◽  
Surface Wind Speed ◽  
Positive Pressure ◽  
Research Station ◽  
Antarctic Research ◽  
Recent Trends

Utilizing surface meteorological data of temperature, pressure and wind of recent two decades, 1991-2010 over Indian Antarctic research station Maitri the trends and variabilities in surface meteorological parameters have been discussed. The trend in mean air temperature at Maitri has been -0.4/decade during past two decades showing no impact of global warming on Maitri surface temperature. There is no trend in surface pressure at Maitri during last two decades. Mean surface wind speed has shown slight increasing trend during the decade 1991-2000 whereas it has shown slight decreasing trend during the decade 2001-2010. However, there are large interannual variations in surface parameters and the linear trends seem to be the result of such variations. During Jan-March of two contrasting monsoon years 2009 and 2010 interesting anomalies in surface pressure at Maitri have been observed. Surface pressure was anomalously lower at Matri in Jan-March of drought year 2009 whereas positive pressure anomalies prevailed during the same period of excess monsoon year 2010. Negative temperature anomalies during January-March over Maitri preceded drought monsoon 2009 and positive anomalies prevailed during the same period before good monsoon 2010.

scholarly journals Characteristics and Applications of the Ground-Based X Band Low Elevation Angle Brightness Temperatures under Low Sea State Based on Measured Data

2020 ◽  
Vol 12 (11) ◽  
pp. 1736
Author(s):  
Zhongqing Cao ◽  
Lixin Guo ◽  
Shifeng Kang ◽  
Xianhai Cheng ◽  
Qingliang Li ◽  
...  
Keyword(s):  
Wind Speed ◽  
Meteorological Data ◽  
Surface Wind ◽  
Elevation Angle ◽  
Surface Wind Speed ◽  
Sea Surface ◽  
Sea State ◽  
Sea Surface Wind Speed ◽  
Sea Surface Wind ◽  
X Band

In ground-based microwave radiometer remote sensing, low-elevation-angle (−3°~3°) radiation data are often discarded because they are considered to be of little value and are often difficult to model due to the complicated mechanism. Based on the observed X-band horizontal polarization low elevation angle microwave radiation data and the meteorological data at the same time, this study investigated the generation mechanism of low elevation angle brightness temperature (LEATB) and its relationship with meteorological data, i.e., temperature, humidity, and wind speed, under low sea state. As a result, one could find that the LEATB was sensitive to the atmosphere at the elevation angle between 1° to 3°, and a diurnal variation of the LEATB reached up to 10 K. This study also found a linear relationship between the LEATB and sea surface wind speed under low sea state at an elevation range from −3° to 0°, i.e., the brightness temperature decreased as the wind speed increased, which was inconsistent with the observations at the elevation angle from −10° to −5°. The variation of the LEATB difference according to the change in the over-the-horizon detection capability (OTHDC) of the shipborne microwave radar was examined to identify the reason for this phenomenon theoretically. The results showed that the LEATB difference was significantly influenced by a change in the OTHDC. Further, this study examined a remote sensing method to extract the sea surface wind speed data from experimental LEATB data under low sea state. The results demonstrated that the X-band horizontal polarization LEATBs were useful to retrieve the sea surface wind speed data at a reasonable accuracy—the root mean square error of 0.02408 m/s. Overall, this study proved the promising potential of the LEATB data for retrieving temperature profiles, humidity profiles, sea surface winds, and the OTHDC.

scholarly journals On Recent Trends in Atmospheric and Limnological Variables in Lake Ontario

2012 ◽  
Vol 25 (17) ◽  
pp. 5807-5816 ◽  
Author(s):  
Anning Huang ◽  
Yerubandi R. Rao ◽  
Weitao Zhang
Keyword(s):  
Surface Water ◽  
Water Temperature ◽  
Air Temperature ◽  
Surface Wind ◽  
Lake Ontario ◽  
Surface Wind Speed ◽  
Surface Mixed Layer ◽  
Surface Water Temperature ◽  
Recent Trends ◽  
Annual Time

Abstract The surface air and water temperatures increased at all seasonal and annual time scales during the last 40 yr in Lake Ontario. The annual mean air and surface water temperatures have increased by 1.43° ±0.39° and 1.26° ±0.32°C, respectively, over 1970–2009. The air temperature increased at a faster rate than the surface water temperature in winter and autumn, whereas in spring and summer the surface water temperature warmed faster than the air temperature. The length of summer stratified season has increased by 12 ± 2 days since the early 1970s due to the increase in water temperature. The decline of surface wind speed over Lake Ontario resulted in a shallower surface mixed layer and enhanced the summer thermal stratification, which increased the summer surface water temperature more rapidly than the air temperature.

Characteristics of the wind regime of Libya based on NCEP / NCAR reanalysis data and surface weather observations

2020 ◽  
Vol 101-102 (3-4) ◽  
pp. 26-32
Author(s):  
Ellina Agayar ◽  
Ali Saleh Abudawah
Keyword(s):  
Wind Speed ◽  
Wind Field ◽  
General Circulation ◽  
Meteorological Data ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Reanalysis Data ◽  
Average Wind Speed ◽  
Weather Observations ◽  
Surface Weather

The surface wind field are formed by the interaction of general circulation mechanisms with the local physical, geographical and climatic characteristics of the region. The success of the implementation of the different weather models is based on the representativeness of the initial information. The paper presents the results of comparing meteorological data, such as the average monthly speed and direction of the surface wind, from the NCEP / NCAR reanalysis archive with data of surface weather observations for the period from 2015 to 2019. Considering the difficulty of obtaining data, the absence of continuous observations at many meteorological stations in Libya, it was decided to analyze the most complete series of observations for the last period and compare it with the model data of reanalysis. Meteorological stations are located in different geographic regions of Libya (Derna, Zuara, Efren, Misurata, Godames, Jagbub, El-Kufra and Ghat). Based on the monthly average values of the surface wind velocity components for past five years, was done a study of the intrannual structure of the wind field over the territory of Libya and maps of the wind field for this period were constructed. The obtained results of comparison of the NCEP / NCAR reanalysis data with Surface weather observations showed a relatively good agreement between the observed and calculated wind. Noted that the wind, according to NCEP data, is some weaker than observed at the stations. The main reasons for this are the complexity and diversity of the topography around the stations, as well as the representativeness between gridded data and meteorological measurements. Analysis of the distribution of the average monthly wind speed over the territory of Libya indicates a tendency for an increase in the surface wind speed from the southwest to the northeast, both as according to the NCEP / NCAR reanalysis data, where the average wind speed doesn’t exceed 4.7 m/s, and according to actual observations 6.7 m/s.

scholarly journals Influence of meteorological parameters on atmospheric CO2 at Bharati, the Indian Antarctic research station

2018 ◽  
Vol 37 (1) ◽  
pp. 1442072 ◽  
Author(s):  
Mahesh Pathakoti ◽  
Sreenivas Gaddamidi ◽  
Biswadip Gharai ◽  
Prijith Sudhakaran Syamala ◽  
Pamaraju Venkata Narasimha Rao ◽  
...  
Keyword(s):  
Meteorological Parameters ◽  
Atmospheric Co2 ◽  
Research Station ◽  
Antarctic Research

Dependence of mesoscale patterns of Trade-wind clouds on environmental conditions: an investigation using satellite and in-situ observations

2020 ◽  
Author(s):  
Sandrine Bony ◽  
Hauke Schulz ◽  
Jessica Vial ◽  
Bjorn Stevens ◽  
Keyword(s):  
Meteorological Data ◽  
Surface Wind ◽  
Cloud Amount ◽  
Surface Wind Speed ◽  
Trade Wind ◽  
Shallow Convection ◽  
Western Atlantic ◽  
Near Surface ◽  
Cloud Patterns

<p>Trade-wind clouds exhibit a large diversity of spatial organizations at the mesoscale. Over the tropical western Atlantic, a recent study has visually identified four prominent mesoscale patterns of shallow convection, referred to as Flowers, Fish, Gravel and Sugar. By using 19 years of satellite and meteorological data, we show that these four patterns can be identified objectively from satellite observations, and that on daily and interannual timescales, the near-surface wind speed and the strength of the lower-tropospheric stability discriminate the occurrence of the different organization patterns. Moreover, we point out a tight relationship between cloud patterns, low-level cloud amount and cloud-radiative effects. The EUREC4A field study taking place upwind of Barbados in Jan-Feb 2020 offers an opportunity to investigate these relationships from an in-situ and process-oriented perspective. Preliminary results will be discussed.</p>

Evaluation of Modeled Lake Breezes Using an Enhanced Observational Network in Southern Ontario: Case Studies

2018 ◽  
Vol 57 (7) ◽  
pp. 1511-1534 ◽  
Author(s):  
Armin Dehghan ◽  
Zen Mariani ◽  
Sylvie Leroyer ◽  
David Sills ◽  
Stéphane Bélair ◽  
...  
Keyword(s):  
Large Scale ◽  
Meteorological Data ◽  
Surface Wind ◽  
Forecast Accuracy ◽  
Surface Wind Speed ◽  
Lake Breeze ◽  
Surface Cooling ◽  
Observational Network ◽  
Lake Breezes ◽  
Mean Square Errors

AbstractCanadian Global Environmental Multiscale (GEM) numerical model output was compared with the meteorological data from an enhanced observational network to investigate the model’s ability to predict Lake Ontario lake breezes and their characteristics for two cases in the Greater Toronto Area—one in which the large-scale wind opposed the lake breeze and one in which it was in the same direction as the lake breeze. An enhanced observational network of surface meteorological stations, a C-band radar, and two Doppler wind lidars were deployed among other sensors during the 2015 Pan and Parapan American Games in Toronto. The GEM model was run for three nested domains with grid spacings of 2.5, 1, and 0.25 km. Comparisons between the model predictions and ground-based observations showed that the model successfully predicted lake breezes for the two events. The results indicated that using GEM 1 and 0.25 km increased the forecast accuracy of the lake-breeze location, updraft intensity, and depth. The accuracy of the modeled lake breeze timing was approximately ±135 min. The model underpredicted the surface cooling caused by the lake breeze. The GEM 0.25-km model significantly improved the temperature forecast accuracy during the lake-breeze circulations, reducing the bias by up to 72%, but it mainly underpredicted the moisture and overpredicted the surface wind speed. Root-mean-square errors of wind direction forecasts were generally high because of large biases and high variability of errors.

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