wind circulation
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2021 ◽  
Vol 10 (6) ◽  
pp. 3228-3239
Author(s):  
Afrizal Mayub ◽  
Leni Hendraini ◽  
Henny Johan ◽  
Fahmizal Fahmizal ◽  
Rendy Wikrama Wardana

This study aims to model climate change based on rainfall, air temperature, pressure, humidity and wind with grADS software and create a global warming module. This research uses 3D model, define, design, and develop. The results of the modeling of the five climate elements consist of the annual average temperature in Indonesia in 2009-2015 which is between 29oC to 30.1oC, the horizontal distribution of the annual average pressure in Indonesia in 2009-2018 is between 800 mBar to 1000 mBar, the horizontal distribution the average annual humidity in Indonesia in 2009 and 2011 ranged between 27-57, in 2012-2015, 2017 and 2018 it ranged between 30-60, during the East Monsoon, the wind circulation moved from northern Indonesia to the southern region Indonesia. During the west monsoon, the wind circulation moves from the southern part of Indonesia to the northern part of Indonesia. The global warming module for SMA/MA produced is feasible to use, this is in accordance with the value given by the validate of 69 which is in the appropriate category and the response of teachers and students through a 91% questionnaire.


MAUSAM ◽  
2021 ◽  
Vol 72 (4) ◽  
pp. 821-834
Author(s):  
PARTHAPRATIM SARKAR ◽  
PRASHANTH JANARDHAN ◽  
PARTHAJIT ROY

The Indian Ocean Dipole (IOD), a climatic anomaly, results in sustained sea surface temperature (SST) variations between tropical western and eastern Indian Ocean temperatures. In this study, we studied the variations to inculcate the teleconnections between IOD and Indian summer monsoon rainfall (ISMR) distribution across the country for the period 1960-2020 for all the three phases of ISMR. We analyzed rainfall, SST and low-level wind circulation anomalies for the above mentioned time horizon. Positive IOD events noticeably resulted in increase in summer monsoon rainfall distribution across the country respectively while its negative counterpart led to decrease in rainfall except for the commencement phase of ISMR. The variations in SST, wind circulation and moisture movement processes across the Indian Ocean characterize significant changes in rainfall during the positive and negative phases of IOD especially during the recent decades (1991-2020). The recent time horizon also witnesses enhanced low-level equatorial jets (LEJ) across the equatorial Indian Ocean and the Arabian Sea during the positive IOD events as compared to the prior decades (1960-1990). The effect of moisture convergence zone is also analyzed which results in above rainfall conditions across northeastern and central India. Conversely, negative IOD events were found to subdue any such moisture movement mechanisms. Furthermore, and additional investigation to analyze the effect of IOD on the retreating/withdrawal monsoon across northeast India has been done and it has been observed that a stronger positive IOD is detrimental to the seasonal rainfall (May- September) over North East India (-0.7 one month lag correlation). Furthermore, the DMI index of April-May presented a clear indication of monsoon activity over the area during the withdrawal or retreating phase of the summer monsoon, i.e., during September.


MAUSAM ◽  
2021 ◽  
Vol 72 (4) ◽  
pp. 821-834
Author(s):  
PARTHAPRATIM SARKAR ◽  
PRASHANTH JANARDHAN ◽  
PARTHAJIT ROY

The Indian Ocean Dipole (IOD), a climatic anomaly, results in sustained sea surface temperature (SST) variations between tropical western and eastern Indian Ocean temperatures. In this study, we studied the variations to inculcate the teleconnections between IOD and Indian summer monsoon rainfall (ISMR) distribution across the country for the period 1960-2020 for all the three phases of ISMR. We analyzed rainfall, SST and low-level wind circulation anomalies for the above mentioned time horizon. Positive IOD events noticeably resulted in increase in summer monsoon rainfall distribution across the country respectively while its negative counterpart led to decrease in rainfall except for the commencement phase of ISMR. The variations in SST, wind circulation and moisture movement processes across the Indian Ocean characterize significant changes in rainfall during the positive and negative phases of IOD especially during the recent decades (1991-2020). The recent time horizon also witnesses enhanced low-level equatorial jets (LEJ) across the equatorial Indian Ocean and the Arabian Sea during the positive IOD events as compared to the prior decades (1960-1990). The effect of moisture convergence zone is also analyzed which results in above rainfall conditions across northeastern and central India. Conversely, negative IOD events were found to subdue any such moisture movement mechanisms. Furthermore, and additional investigation to analyze the effect of IOD on the retreating/withdrawal monsoon across northeast India has been done  and it has been observed that a stronger positive IOD is detrimental to the seasonal rainfall (May- September) over North East India (-0.7 one month lag correlation). Furthermore, the DMI index of April-May presented a clear indication of monsoon activity over the area during the withdrawal or retreating phase of the summer monsoon, i.e., during September.


2020 ◽  
Vol 3 (5) ◽  
pp. 483-491
Author(s):  
CORENTIN JOUAULT ◽  
ANDRÉ NEL

Palaeobiogeographic hypotheses need to be based on accurate palaeomaps and phylogenies of the concerned clades with a fossil record as complete as possible. Here we re-analyse the palaeobiogeography of the small fly family Scenopinidae, based on its first record in the mid-Cretaceous Burmese amber that we describe herein as Burmaprorates alagracilis gen. et sp. nov. and we assign to the subfamily Proratinae. At that time, the corresponding palaeobiota was an isolated island in the Southern part of the Tethys Ocean far away from the Laurasian plate and with general wind circulation unfavorable for aerial transport from Laurasia to the “Burmese Terrane”. Our results challenge and question the hypothesis of a North-Central American origin for the Scenopinidae at the beginning of the Cretaceous, and support a new hypothesis of a South Gondwanan origin.


Climate ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 128
Author(s):  
Alejandro Salcido ◽  
Susana Carreón-Sierra ◽  
Ana-Teresa Celada-Murillo

According to the Mexico City Emissions Inventory, mobile sources are responsible for approximately 86% of nitrogen oxide emissions in this region, and correspond to a NOx emission of 51 and 58 kilotons per year in Mexico City and the State of Mexico, respectively. Ozone levels in this region are often high and persist as one of the main problems of air pollution. Identifying the main scenarios for the transport and dispersion of air pollutants requires the knowledge of their flow patterns. This work examines the surface flow patterns of air pollutants (NO2, O3, SO2, and PM10) in the area of Mexico City (a region with strong orographic influences) over the period 2001–2010. The flow condition of a pollutant depends on the spatial distribution of its concentration and the mode of wind circulation in the region. We achieved the identification and characterization of the pollutant flow patterns through the exploitation of the 1-hour average values of the pollutant concentrations and wind data provided by the atmospheric monitoring network of Mexico City and the application of the k-means method of cluster analysis. The data objects for the cluster analysis were obtained by modeling Mexico City as a 4-cell spatial domain and describing, for each pollutant, the flow state in a cell by the spatial averages of the horizontal pollutant flow vector and its gradients (the divergence and curl of the flow vector). We identified seven patterns for wind circulation and nine patterns for each of NO2, O3, PM10, and SO2 pollutant flows. Their seasonal and annual average intensities and probabilities of occurrence were estimated.


2019 ◽  
Vol 59 (1) ◽  
pp. 5-11
Author(s):  
A. P. Mirabel ◽  
N. V. Vakulenko

A model of an advective thermocline is proposed for the case of continuously stratified Sverdrup circulation with a ventilated layer caused by the divergence of flows in the Ekman layer: an immiscible layer with homogenized vorticity and a layer of abyssal liquid, which applies to anticyclonic gyre waters. The results of calculations for the Atlantic Ocean (region 15-52°N, 00-63°E) made with this model are presented. With an abyssal density of 28.0, the values of the surface density and density of the unventilated layer grow to the north from 24.2 to 27.0 and from 27.8 to 27.9, respectively, with an almost zonal distribution, i.e. ventilation zones have latitudinal circles. From calculations of the depths of wind circulation, it follows that the ventilating layer is as deep as 900 m in the north-western region and raises to 250 m in the southern and eastern parts of the basin. The same tendency is traced for the depth of the gyre, but here there is an increase in depth from 500 to 1500 m. The active dynamics in the ventilating layer and the shadow area on the eastern border are noted. The structure of the thermocline is demonstrated with a typical zonal section, characterizing a much larger isopycnic increment for ventilated layers than in non-ventilated layers.


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