scholarly journals A view of global monsoons in observed and model climatology

MAUSAM ◽  
2021 ◽  
Vol 49 (1) ◽  
pp. 79-94
Author(s):  
K.R. SAHA ◽  
HUUG M. VAN DEN DOOL ◽  
SURANJANA SAHA
Keyword(s):  
High Mountain ◽  
Monsoon Circulation ◽  
Good Correspondence ◽  
Operational Model ◽  
Global Monsoon ◽  
Mountain Ranges ◽  
Summer Hemisphere ◽  
Environmental Prediction ◽  
East West ◽  
Temperature Surface

A 17 - year (1979-95) January and July climatology obtained from a T 62/ 28 -level version of the National Centers for Environmental Prediction (NCEP) global spectral operational model is compared with a mean observed climatology for the same period obtained from its reanalysis project, with a view to finding out how well it captures some of the well-thrown characteristics of the global monsoon circulation generated seasonally by differential heating of the earth's surface by the sun in the course of its annual oscillation about the equator. Good correspondence between the two is found in the fields of mean monthly anomaly (deviation of monthly mean from the annual mean) of surface temperature, surface pressure, atmospheric circulation and total rainfall over most parts of the globe, barring a few exceptions mostly in circulation and rainfall.   Large diversity in the distribution and intensity of monsoon found over different regions due to land-sea configurations, cold and warm ocean surfaces and high mountain ranges appears to be well reflected in model and observed climatology. However, the concept of a single equatorial trough moving from one hemisphere to the other to cause advance and onset of monsoon appears to fail especially over warm oceans, where there appears to be evidence in favour of two troughs, one in each hemisphere. It is the equatorial trough in the summer hemisphere that moves to bring up the monsoon in that hemisphere. There appears to be some evidence to suggest an east-west movement of monsoons between major continents and oceans.

scholarly journals An Evaluation of Precipitation Forecasts from Operational Models and Reanalyses Including Precipitation Variations Associated with MJO Activity

2010 ◽  
Vol 138 (12) ◽  
pp. 4542-4560 ◽  
Author(s):  
John E. Janowiak ◽  
Peter Bauer ◽  
Wanqiu Wang ◽  
Phillip A. Arkin ◽  
Jon Gottschalck
Keyword(s):  
Prediction Models ◽  
Coupled Model ◽  
Warm Season ◽  
Temporal Correlation ◽  
Operational Model ◽  
Temporal Correlations ◽  
Operational Models ◽  
Environmental Prediction ◽  
The Tropics ◽  
Model Precipitation

Abstract In this paper, the results of an examination of precipitation forecasts for 1–30-day leads from global models run at the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) during November 2007–February 2008 are presented. The performance of the model precipitation forecasts are examined in global and regional contexts, and results of a case study of precipitation variations that are associated with a moderate to strong Madden–Julian oscillation (MJO) event are presented. The precipitation forecasts from the ECMWF and NCEP operational prediction models have nearly identical temporal correlation with observed precipitation at forecast leads from 2 to 9 days over the Northern Hemisphere during the cool season, despite the higher resolution of the ECMWF operational model, while the ECMWF operational model forecasts are slightly better in the tropics and the Southern Hemisphere during the warm season. The ECMWF Re-Analysis Interim (ERA-Interim) precipitation forecasts perform only slightly worse than the NCEP operational model, while NCEP’s Climate Forecast System low-resolution coupled model forecasts perform the worst among the four models. In terms of bias, the ECMWF operational model performs the best among the four model forecasts that were examined, particularly with respect to the ITCZ regions in both the Atlantic and Pacific. Local temporal correlations that were computed on daily precipitation totals for day-2 forecasts against observations indicate that the operational models at ECMWF and NCEP perform the best during the 4-month study period, and that all of the models have low to insignificant correlations over land and over much of the tropics. They perform the best in subtropical and extratropical oceanic regions. Also presented are results that show that striking improvements have been made over the past two decades in the ability of the models to represent precipitation variations that are associated with MJO. The model precipitation forecasts exhibit the ability to characterize the evolution of precipitation variations during a moderate–strong period of MJO conditions for forecast leads as long as 10 days.

scholarly journals Avalanche situation in Turkey and back calculation of selected events

2014 ◽  
Vol 14 (5) ◽  
pp. 1145-1154 ◽  
Author(s):  
A. Aydin ◽  
Y. Bühler ◽  
M. Christen ◽  
I. Gürer
Keyword(s):  
Simulation Software ◽  
High Mountain ◽  
Identification Algorithm ◽  
Black Sea Region ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
Back Calculation ◽  
Elevation Model ◽  
Very High ◽  
Rapid Mass

Abstract. In Turkey, an average of 24 people die in snow avalanches every year, mainly in the eastern part of Anatolia and in the eastern Black Sea region, where high-mountain ranges are close to the sea. The proportion of people killed in buildings is very high (87%), especially in comparison to other European countries and North America. In this paper we discuss avalanche occurrence, the climatic situation and historical avalanche events in Turkey; in addition, we identify bottlenecks and suggest solutions to tackle avalanche problems. Furthermore, we have applied the numerical avalanche simulation software RAMMS (rapid mass movements simulation) combined with a (digital elevation model) DEM-based potential release zone identification algorithm to analyze the catastrophic avalanche events in the villages of Üzengili (Bayburt province) in 1993 and Yaylaönü (Trabzon province) in 1981. The results demonstrate the value of such an approach for regions with poor avalanche databases, enabling the calculation of different scenarios and the estimation of run-out distances, impact pressure and flow height.

Acricotopus indet. morphotype incurvatus: Description and genetics of a new Orthocladiinae (Diptera: Chironomidae) larval morphotype from the Tibetan Plateau

Zootaxa ◽  
2019 ◽  
Vol 4656 (3) ◽  
pp. 535-544
Author(s):  
ANDREAS LAUG ◽  
LADISLAV HAMERLÍK ◽  
STEN ANSLAN ◽  
STEFAN ENGELS ◽  
FALKO TURNER ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
Mitochondrial Coi ◽  
Mountain Ranges ◽  
Central Tibetan Plateau ◽  
Peculiar Form ◽  
Close Proximity ◽  
Coi Sequences ◽  
Complex Formations

High mountain ranges such as the Tibetan Plateau with an average altitude above 4500 m are topographically complex formations. Elevational gradients, physiographic diversity and climatic heterogeneity have led to highly biodiverse ecosystems in these regions. Mountain ranges can be seen as cradles of evolution and harbour, due to their unique characteristics, a high number of highly adapted species. At the same time these areas are hard to access and therefore taxonomic information is limited. Here we describe a new Acricotopus (Diptera: Chironomidae: Orthocladiinae) larval morphotype occurring in lakes and ponds of differing salinity and water depths located on the Southern and Central Tibetan Plateau. The description is based on larvae and their genetics (ribosomal 18S, 28S and mitochondrial COI sequences) collected from a shallow pond in close proximity to the large saline lake Selin Co. Larvae of Acricotopus indet. morphotype incurvatus are characterized by a mentum with a cluster of lateral teeth, partially folded inwards, a mandible with a toothed lobe in addition to four inner teeth and a sclerotized plate positioned behind the mentum. Up to now, these morphological features have only been found in early instars of other Acricotopus species. The proposed morphotype name is inspired by the peculiar form of the mentum. 

Description of two new species of Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from the Western Ghats of Kerala, India

Zootaxa ◽  
2018 ◽  
Vol 4459 (1) ◽  
pp. 85 ◽  
Author(s):  
VIVEK PHILIP CYRIAC ◽  
ALEX JOHNY ◽  
P. K. UMESH ◽  
MUHAMED JAFER PALOT
Keyword(s):  
New Species ◽  
Western Ghats ◽  
Morphological Characters ◽  
High Elevation ◽  
High Mountain ◽  
Mountain Ranges ◽  
Two New Species ◽  
Southern Western Ghats ◽  
High Elevation Forests ◽  
The Western Ghats

Two new species of geckos of the genus Cnemaspis Strauch, 1887 are described from the southern Western Ghats of Kerala. Both species are medium to large sized Cnemaspis and can be differentiated from all other Indian congeners by a suite of distinct morphological characters. Both species are found in the high elevation forests of the two major massifs—       Anaimalai Hills and Agasthyamalai Hills and are presently known to have very restricted distributional ranges. The discovery of these novel species highlights the understudied diversity of reptiles in the high mountain ranges of the Western Ghats. 

scholarly journals The topographic evolution of the Tibetan Region as revealed by palaeontology

2020 ◽  
Author(s):  
Robert A. Spicer ◽  
Tao Su ◽  
Paul J. Valdes ◽  
Alexander Farnsworth ◽  
Fei-Xiang Wu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Landscape Evolution ◽  
The Tibetan Plateau ◽  
Mountain Ranges ◽  
The Past ◽  
Complex Interactions ◽  
New Synthesis ◽  
The Rich ◽  
Topographic Evolution ◽  
East West

AbstractThe Tibetan Plateau was built through a succession of Gondwanan terranes colliding with Asia during the Mesozoic. These accretions produced a complex Paleogene topography of several predominantly east–west trending mountain ranges separated by deep valleys. Despite this piecemeal assembly and resultant complex relief, Tibet has traditionally been thought of as a coherent entity rising as one unit. This has led to the widely used phrase ‘the uplift of the Tibetan Plateau’, which is a false concept borne of simplistic modelling and confounds understanding the complex interactions between topography climate and biodiversity. Here, using the rich palaeontological record of the Tibetan region, we review what is known about the past topography of the Tibetan region using a combination of quantitative isotope and fossil palaeoaltimetric proxies, and present a new synthesis of the orography of Tibet throughout the Paleogene. We show why ‘the uplift of the Tibetan Plateau’ never occurred, and quantify a new pattern of topographic and landscape evolution that contributed to the development of today’s extraordinary Asian biodiversity.

scholarly journals Seasonality and spatial variability of dynamic precipitation controls on the Tibetan Plateau

2016 ◽  
Author(s):  
Julia Curio ◽  
Dieter Scherer
Keyword(s):  
Tibetan Plateau ◽  
Spatial Variability ◽  
Water Cycle ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
Precipitation Distribution ◽  
Mountain Ranges ◽  
Boundary Layer Height ◽  
Dynamic Factors ◽  
Vertical Wind Speed

Abstract. The Tibetan Plateau (TP) is the origin of many large Asian rivers, which provide moisture for large regions in South and East Asia. Therefore, the water cycle on the TP and adjacent high mountain ranges and especially the precipitation distribution plays an important role for the water availability for billions of people in the regions downstream of the TP. Based on the High Asia Refined analysis (HAR) we analyse the influence of dynamic factors on precipitation, enhancing or suppressing precipitation development. We selected six precipitation controls, the horizontal and vertical wind speed at 300 hPa and in about two kilometres above ground, the atmospheric water transport, and the planetary boundary layer height. Focus of the study are the seasonality and the spatial variability of these precipitation controls and their dominant patterns. The results show that precipitation controls have different effects on precipitation in different regions and seasons. This depends mainly on the type of precipitation, convective or frontal/cyclonic precipitation. Additionally, the study reveals that the mid-latitude westerlies have a high impact on precipitation distribution on the TP and its surrounding year-round.

Lhasa

1946 ◽  
Vol 78 (1-2) ◽  
pp. 23-31
Author(s):  
E. H. C. Walsh
Keyword(s):  
High Mountain ◽  
Large Country ◽  
Mountain Ranges ◽  
The World

Although Tibet is a large country, over 900 miles in its greatest length and over 800 miles in its greatest width, with a frontier of over 2,000 miles, very little was known about it before Sir Francis Younghusband's Expedition in 1903–4. The reason for this is its frontiers of high mountain ranges, some of them the highest in the world.

scholarly journals Seasonality and spatial variability of dynamic precipitation controls on the Tibetan Plateau

2016 ◽  
Vol 7 (3) ◽  
pp. 767-782 ◽  
Author(s):  
Julia Curio ◽  
Dieter Scherer
Keyword(s):  
Wind Speed ◽  
Tibetan Plateau ◽  
Spatial Variability ◽  
Water Cycle ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
Dominant Type ◽  
Precipitation Distribution ◽  
Mountain Ranges ◽  
Vertical Wind Speed

Abstract. The Tibetan Plateau (TP) is the origin of many large Asian rivers, which provide water resources for large regions in south and east Asia. Therefore, the water cycle on the TP and adjacent high mountain ranges, in particular the precipitation distribution and variability play an important role for the water availability for billions of people in the downstream regions of the TP. The High Asia Refined analysis (HAR) is used to analyse the dynamical factors that influence precipitation variability in the TP region, including the factors resulting in the enhancement and suppression of precipitation. Four dynamical fields that can influence precipitation are considered: the 300 hPa wind speed and wind speed 2 km above ground, the 300 hPa vertical wind speed, and the atmospheric water transport. The study focusses on the seasonality and the spatial variability of the precipitation controls and their dominant patterns. Results show that different factors have different effects on precipitation in different regions and seasons. This depends mainly on the dominant type of precipitation, i.e. convective or frontal/cyclonic precipitation. Additionally, the study reveals that the midlatitude westerlies have a high impact on the precipitation distribution on the TP and its surroundings year-round and not only in winter.

MAKNA FILOSOFIS BANGUNAN KRATON SURAKARTA

2016 ◽  
Vol 2 (12) ◽  
Author(s):  
Purwadi
Keyword(s):  
Social Life ◽  
Capital City ◽  
Symbolic Meaning ◽  
High Mountain ◽  
Mountain Ranges ◽  
The City

This article will describe about symbolic meaning and phylosophy value in Kraton Surakarta.In 1745 Sunan Paku Buwono II moved his court to nearby Surakarta where he had built a new palace. When the king ordered to move the capital city of Kartasura eastward to the banks of Javas longest river, it was certainly not without reasons. At that time over land communica­tion was scarce because of inaccesible swamps, high mountain ranges and impenetrable forests. But the city must have its outlet, its contact with outer islands and Bengawan then was the only economic and social life line. Keyword: Kraton Surakarta, phylosophy, symbolic

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