Showing papers on "Monsoon published in 1988"
Book•
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TL;DR: Wang et al. as discussed by the authors studied the effect of topography and elevation on the seasonal distribution of precipitation in China and found that the topography of land and sea and the nature of the underlying ground can influence the seasonal variation of precipitation.
Abstract: 1 Introduction.- 1.1 Aims and Concept of the Study.- 1.2 Climate Data.- 1.3 Review of Climate Studies on China.- 2 Controlling Factors of the Climate.- 2.1 Latitude, Longitude and Location.- 2.2 Topography and Landforms.- 2.3 Distribution of Land and Sea and Nature of the Underlying Ground.- 2.4 Seasons.- 3 Circulation.- 3.1 Seasonal Pressure Distribution at Sea Level.- 3.2 Seasonally Prevailing Winds and Air Masses.- 3.3 Winter and Summer Monsoon.- 3.3.1 Characteristics of the Monsoon in General.- 3.3.2 Onset and Duration of the Winter Monsoon.- 3.3.3 Periods of Active and Weak Winter Monsoon.- 3.3.4 Damage Due to Strong Cold Outbreaks of Winter Monsoon.- 3.3.5 Onset and Duration of the Summer Monsoon.- 3.3.6 Some Characteristics of the Summer Monsoon.- 3.4 Frontology.- 3.4.1 Mean Front Position in January and July.- 3.4.2 The Stationary Fronts in February and March as well as in the Pre-Typhoon Season in South China.- 3.4.3 Some Characteristics of the Mei-Yu Front.- 3.5 The Transient Disturbances.- 3.5.1 The Upper Westerly Troughs in the Westerlies.- 3.5.2 Extratropical Cyclones and Anticyclones.- 3.5.3 Typhoons.- 4 Temperature.- 4.1 Mean Annual Air Temperature Distribution.- 4.2 Mean Seasonal Temperature Distribution.- 4.3 Annual Range and Annual Variation of Temperature.- 4.4 Onset and End of Certain Limited Temperatures and Their Duration.- 4.4.1 Mean Daily Air Temperature ? 0 C.- 4.4.2 Mean Daily Air Temperature ? 10 C.- 4.4.3 Maximum Daily Air Temperature ? 35 C.- 4.4.4 Other Extreme Limited Temperatures.- 4.5 Vertical Distribution of Temperature.- 4.6 Comparison of Temperature at the Same Latitude.- 4.7 Diurnal Range of Temperature.- 4.8 Interannual Variability of Temperature.- 4.8.1 Variability of Annual Mean Temperature.- 4.8.2 Variability of Monthly Mean Temperatures.- 4.9 Historical-Climatic Change of Temperature During the last 5,000, 500 and 100 Years.- 5 Precipitation.- 5.1 Mean Annual Precipitation Distribution.- 5.2 Mean Seasonal Precipitation Distribution.- 5.3 Annual Variation of Precipitation.- 5.3.1 Specific Precipitation Types and Their Distribution.- 5.3.2 Variation of Wet and Dry Months over Space and Time.- 5.3.3 Summer Precipitation.- 5.4 Interannual Precipitation Variability.- 5.4.1 Variability of Annual Precipitation.- 5.4.2 Variability of Monthly Precipitation.- 5.4.3 Variability of Annual and Monthly Precipitation at Beijing.- 5.5 Precipitation Frequency Expressed in Rainy Days.- 5.6 Precipitation Intensity.- 5.7 Rainstorms and Certain Events of Heavy Rainfall.- 5.8 Diurnal Variation of Precipitation.- 5.9 Influence of Topography and Elevation on Precipitation.- 5.9.1 Influence of the Exposition of Slopes on Precipitation.- 5.9.2 Effect of Elevation on Prefipitation.- 5.10 Historical Change of Precipitation.- 5.11 Snow.- 5.11.1 Mean Length of Snow Cover Period.- 5.11.2 Number of Snowfall Days.- 5.11.3 Maximum Depth of Snow.- 5.11.4 Altitude of the Snow Line.- 6 Cloudiness and Sunshine.- 6.1 Mean Annual Cloudiness and January and July Amount.- 6.2 Sunshine.- 6.2.1 Annual Sunshine Duration.- 6.2.2 Sunshine Duration in January and July and Annual Variation.- 6.3 Global Radiation.- 6.4 Fog.- 7 Surface Wind.- 7.1 Mean and Extreme Wind Velocities.- 7.2 Local Wind Systems.- 7.2.1 Mountain and Valley Breezes.- 7.2.2 Land and Sea Breezes, Lake Breeze.- 7.2.3 Plateau Monsoon.- 7.2.4 Local Dry and Hot Winds.- 8 Climate Classification and Division of China.- 8.1 General Objectives and Fundamentals of Climate Regionalization.- 8.2 China Within Global Climate Classifications.- 8.3 National Climate Classifications of China.- 8.4 Climate Division of China According to Huang Bing-wei (1986).- 9 Climate Zones of China.- 9.1 Cold Temperate Zone (I).- 9.2 Middle Temperate Zone (II).- 9.3 Warm Temperate Zone (III).- 9.4 Northern Subtropical Zone (IV).- 9.5 Middle Subtropical Zone (V).- 9.6 Southern Subtropical Zone (VI).- 9.7 Peripheral Tropical Zone (VII).- 9.8 Middle Tropical Zone (VIII).- 9.9 Southern Tropical Zone (IX).- 9.10 Alpine Plateau Zone (H0).- 9.11 Subalpine Plateau tone (HI).- 9.12 Temperate Plateau Zone (HII).- Appendix: Climate Tables.- References.
345 citations
TL;DR: In this article, a documentation of the seasonal and intraseasonal rainfall climatology of summer monsoon rainfall over East Asia, using monthly and 10-d precipitation data from East Asian stations.
Abstract: This paper presents a documentation of the seasonal and intraseasonal rainfall climatology of summer monsoon rainfall over East Asia, using monthly and 10-d precipitation data from East Asian stations. These data are then related to satellite measurements of longwave radiation and large-scale circulation field. Major rainfall regimes and multiple monsoon onsets are identified, indicating that, in general, monsoon rainfall over East Asia evolves with wavelike progression from north to south from April to September. Abrupt changes in the major rainbands are related to the phase-locking between intraseasonal oscillations found in this study, such as the 40-d and 20-d rainfall fluctuations, and the seasonal monsoon cycle.
323 citations
TL;DR: A review of existing literature and data on seasonal patterns in East Africa's coastal waters indicates distinct seasonality in physical, chemical and biological oceanographic parameters as discussed by the authors, which is dictated by the behavior of the Inter-Tropical Convergence Zone (ITCZ) which creates two distinct seasons the northeast and southeast monsoons.
Abstract: A review of existing literature and data on seasonal patterns in East Africa's coastal waters indicates distinct seasonality in physical, chemical and biological oceanographic parameters. Seasonal patterns are dictated by the behavior of the Inter-Tropical Convergence Zone (ITCZ) which creates 2 distinct seasons the northeast and southeast monsoons. SE monsoon (March to October) meteorological parameters are characterized by high cloud cover, rainfall, river discharge, terrestrial runoff and wind energy while solar insolation and temperatures are low; SE monsoon oceanographic parameters are characterized by cool water, a deep thermocline, high water-column mixing and wave energy, fast currents, low s a h ~ t y and high phosphorus. These parameters are reversed during the NE monsoon. Nitrogen availability and planktonic primary productivity are high along the Somali coast and estuarine and river discharge areas during the southeast monsoons due to nutrient upwelling and terrestrial runoff. In near-shore waters off Tanzania, nitrogen fixation is the major source of nitrogen and is highest during NE monsoons when the water column is stable. Coral reef benthic algal biomass and diversity is greatest during the SE monsoons. Fish catch and reproduction are highest during NE monsoons in Kenya and Tanzania. Transition periods between monsoons may also be important times in determining productivity and reproduction.
269 citations
TL;DR: Numerical simulations with a global atmospheric circulation model suggest that largescale variations in the amount of snowfall over Eurasia in the springtime are linked to the subsequent strength of the Asian summer monsoon, challenging the current dogma that the ENSO phenomenon is solely the result of close coupling between the atmosphere and ocean.
Abstract: Numerical simulations with a global atmospheric circulation model suggest that largescale variations in the amount of snowfall over Eurasia in the springtime are linked to the subsequent strength of the Asian summer monsoon. Large-scale changes in Eurasian snow cover are coupled to larger scale changes in the global climate system. There is a large, strong teleconnection to the atmospheric field over North America. The model results also show snow cover effects to subsequently alter other climatic fields known to be intimately associated with the El Nino-Southern Oscillation (ENSO) phenomenon. Thus the model results seem to challenge the current dogma that the ENSO phenomenon is solely the result of close coupling between the atmosphere and ocean by suggesting that processes over continental land masses may also have to be considered.
228 citations
TL;DR: In this article, an atmospheric general circulation model coupled with a 50m mixed layer ocean was used to study the sensitivity of the climate to the changed seasonal and latitudinal distribution of solar radiation for 9000 years ago.
Abstract: Experiments were made with an atmospheric general circulation model coupled to a 50-m mixed layer ocean in order to study the sensitivity of the climate to the changed seasonal and latitudinal distribution of solar radiation for 9000 years ago. At 9000 years B.P. (before present), when perihelion was in July (compared to January at present) and the axial tilt was greater than at present, the July (January) solar radiation in the northern hemisphere was increased (decreased) by about 7% compared to that at present. The coupled atmosphere/ocean model simulated warmer continents in summer and intensified northern summer monsoons at 9000 years B.P., compared to the present, that were similar to previous results with an atmospheric model. Owing to small positive feedbacks, the coupled atmosphere/ocean model produced a slightly greater intensification of the 9000-year B.P. monsoon than the atmospheric model. The ocean temperature changes were less than 1 K and lagged the solar radiation changes; the 9000-year B.P. ocean was warmer in September and colder in March than the control simulation. The annual-average ocean temperature was slightly lower in the tropics because the annual-average incoming solar radiation was lower at 9000 years B.P. In middle latitudes the annual-average ocean temperature was decreased because of feedbacks associated with seasonality. In high northern latitudes, sea ice thickness was reduced at 9000 years B.P. in response to increased summer and annual-average solar radiation. The reduced high-latitude sea ice caused somewhat warmer wintertime conditions over the northwestern portions of northern continents.
221 citations
TL;DR: In this article, the dates of onset of the southwest monsoon over south and north Kerala have been derived on the basis of objective criteria for the years 1901 to 1980 using daily mean rainfall from dense rain gauge networks.
Abstract: Utilising daily mean rainfall from dense rain gauge networks, the dates of onset of the southwest monsoon over south and north Kerala have been derived on the basis of objective criteria for the years 1901 to 1980. These dates have been compared with the onset dates as per records of the India Meteorological Department. Statistics of the onset dates are presented. The mean onset date for south Kerala is found to be 30 May and for north Kerala 1 June with a standard deviation of about 9 days in both cases. The sharp increase in rainfall that heralds the onset of the monsoon is highlighted by superposed epoch analysis. The prevailing notion that rainfall from pre-monsoon thunderstorms progressively increases and merges with the monsoon rainfall is shown to be not valid.
200 citations
Book•
01 Dec 1988
TL;DR: In this article, the global picture atmospheric water as a part of the hydrological cycle evaporation, transpiration and evapotranspiration determination of evapore and transpiration rates.
Abstract: Part 1 Water in the atmosphere: the global picture atmospheric water as a part of the hydrological cycle evaporation, transpiration and evapotranspiration determination of evaporation and transpiration rates. Part 2 The formation of clouds: setting the stage uplift in the atmosphere cloud types and morphology. Part 3 Precipitation formation: not all clouds precipitate precipitation form precipitation characteristics precipitation type. Part 4 Local and small-scale precipitation: shower and storm generation and movement multicell and supercell storms squall-line storms mesoscale convective complexes locally-forced precipitation. Part 5 Synoptic-scale precipitation - temperate systems: small-scale synoptic features the temperate latitude frontal depression. Part 6 Synoptic-scale precipitation - tropical systems: atmospheric circulation in the tropics disturbance in the tropics monsoon circulations longer term larger scale precipitation variations in the tropics. Part 7 Precipitation measurement and observation: measurement by gauges - by ground-based radar - by satellite. Part 8 Precipitation analysis - in time: precipitation climatologies trends and oscillations system signatures probability studies probable maximum precipitation (PMP). Part 9 Precipitation analysis - in space: mapping precipitation areal mean precipitation the spatial organization of precipitation.
134 citations
TL;DR: In this paper, the authors studied the rainfall pattern in time and space within the Masai Ecosystem of northern Tanzania using rainfall data of sixteen stations within the area and found that rainfall in the dry season is caused by thunderstorm activity, and no relation between rainfall and altitude exists during this time of the year.
Abstract: The rainfall pattern in time and space within the Masai Ecosystem of northern Tanzania was studied using rainfall data of sixteen stations within the area. Annual amounts of rainfall were found to be unpredictable, and the annual deviations of the long-term mean annual rainfall were without cyclic trends for the individual stations. However, the pooled rainfall data of the different stations show that series of wet and dry years alternate. Total annual rainfall increases with altitude and the variability in rainfall decreases with altitude. It appears that rainfall in the dry season is caused by thunderstorm activity, and no relation between rainfall and altitude exists during this time of the year. Rainfall in the wet season shows a very different spatial relationship, indicating the effects of the monsoon, and, especially during the long rains, rainfall increases with altitude. Different seasons can be discerned, and the data indicate that the amount of rain in the long rainy season is more predictable than the amount in the short rainy season. The differences are discussed briefly with regard to plant phenology patterns and grass growth.
117 citations
114 citations
TL;DR: In this paper, the inception of the Kuroshio branch in the Taiwan strait starts from such an intrusion event, and the first event of the intrusion of warm waters from the eddy into, or even through, the Taiwan Strait usually appears when the NE wind weakens from a strong cold-air outbreak in winter or early spring.
105 citations
TL;DR: In this article, three monsoon patterns appear to be indicated: (1) a full glacial monsoon pattern (18000−15000 yr BP), which induced a cold and dry climate favouring loess accumulation in steppe conditions; (2) an interglacial monoon pattern (last interglastic and Holocene) in which a warm humid climate prevailed with deciduous forests, leaving palaeosols interbedded within the loess sequence; and (3) a transitional or interstadial monoon patterns (50 000−23 000 yr BP
Abstract: China's Loess Plateau was formed under special conditions. The tectonic movement, topographical characteristics, and monsoon patterns combined to create a favourable environment for the accumulation of thick loessic deposits. The Loess Plateau itself is part of the ‘Monsoon Triangle’ of China, a region very susceptible to climatic changes. Throughout the Upper Pleistocene the palaeoenvironment on the Loess Plateau alternated from steppe, to deciduous forest and coniferous forest, in response to shifts in the atmospheric circulation. Three monsoon patterns appear to be indicated: (1) a full glacial monsoon pattern (18000–15000 yr BP) which induced a cold and dry climate favouring loess accumulation in steppe conditions; (2) an interglacial monsoon pattern (last interglacial and Holocene) in which a warm humid climate prevailed with deciduous forests, leaving palaeosols interbedded within the loess sequence; and (3) a transitional or interstadial monsoon pattern (50 000–23 000 yr BP) in which the climate was cold and humid in the Loess Plateau, encouraging the development of coniferous forest.
TL;DR: A survey of figures, maps and tables can be found in this paper, along with a glossary on spelling and currency, weights and measures, and a list of abbreviations and notes.
Abstract: List of figures, maps and tables Glossary Notes on spelling and currency, weights and measures Preface 1. Maritime trade in Asia 2. Imperial foundations: the Estado da India and Macao 3. Population, personalities, and communal power 4. Country traders and Crown monopoly 5. Merchants and markets 6. Country traders and the search for markets 7. Imperial relations: Macao and the Estado de India: 8. Imperial survival: Sino-Portuguese relations from Ming to Ch'ing 9. Macao, companies and country traders: the other Europeans in China 10. Conclusion List of abbreviations and notes Bibliography Index.
TL;DR: Large-scale spatial and temporal stability of the two mutually exclusive ecosystems, mangrove forest and freshwater wetland, contains considerable small- scale variation and maximum diversity and variability occurred during the time of least environmental stability in the transition phase.
Abstract: The coastal freshwater wetlands of western Arnhem Land in the monsoon tropics of the Northern Territory of Australia are subject to new and increasing pressures from a range of land uses. Wetland history is needed as a basis for management decisions. Radiocarbon dates and pollen analyses of samples from fifty surveyed sites on the Magela floodplain show mangrove vegetation encroaching as sea level rose from about 8000 BP to 6000 BP. The extensive Rhizophora forest established at that time lasted until about 3000 BP, when the sediments built up above the upper tidal limit for these mangroves. Avicennia and other mangrove genera became more abundant in the subsequent transition phase. The floodplain has been a freshwater wetland since about 1300 BP. High resolu- tion pollen analyses of contiguous 1 cm samples through the transition at two sites show parallel sequences of vegetation changes. Large-scale spatial and temporal stability of the two mutually exclusive ecosystems, mangrove forest and freshwater wetland, contains considerable small- scale variation. Maximum diversity and variability occurred during the time of least environmental stability in the transition phase. Vegetation change was discontinuous, with each major shift followed by variation around a new mean. A rise in sea level of 0.5-1.0 m could destroy the present freshwater wetland and allow some mangroves to return to the Magela.
TL;DR: In this paper, a two-dimensional compressible moist cloud model is applied to study the physics underlying orographic-convective precipitation over this area, and the initial fields of thermodynamic variables are specified using observed data gathered upstream of the offshore precipitating systems over the Arabian Sea.
Abstract: When the western coast of India lies in the path of the low-level west-southwest wind crossing the Arabian Sea during the summer monsoon season, deep convection frequently develops over the ocean off the coast. In such a situation, the maximum rainfall occurs near the coast, not over the Western Ghats. In order to study the physics underlying orographic-convective precipitation over this area, a two-dimensional compressible moist cloud model is applied. The model is written in terrain-following coordinates and includes the Coriolis force and a planetary boundary layer parameterization. The initial fields of thermodynamic variables are specified using observed data gathered upstream of the offshore precipitating systems over the Arabian Sea. Two wind profiles are considered: vertically uniform and nonuniform flows. The latter profile represents a monsoonal westerly jet at low levels and easterlies in the layer above 5 km. Three cases are considered for each wind profile by including or omitting mo...
DOI•
01 Jul 1988TL;DR: In this article, the authors used monthly mean winds and currents to identify the driving mechanisms of seasonal coastal circulation in the North Indian Ocean and found that the surface circulation off Arabia is typical of a wind-driven system with similar patterns of longshore current and wind stress.
Abstract: Monthly-mean winds and currents have been used to identify the driving mechanisms of seasonal coastal circulation in the North Indian Ocean. The main conclusions are: (i) the surface circulation off Arabia is typical of a wind-driven system with similar patterns of longshore current and wind stress; (ii) circulation off the west coast of India is consistent with the dynamics of a wind-driven eastern boundary current only during the southwest monsoon. During the northeast monsoon it is possible that the influence of the interior flow is important. (iii) There are at least three mechanisms that influence the surface circulation off the east coast of India: wind-stress, influence of fresh-water run off and contribution of the interior flow. It is difficult at present to assess the relative importance of these three processes.
TL;DR: In this paper, rainfall and temperature data during the period 1901-1982 were studied for the northwest Indian region consisting of the meteorological subdivisions of Punjab, Haryana, west Rajasthan, east and west Madhya Pradesh.
Abstract: Rainfall and temperature data during the period 1901–1982 are studied for the northwest Indian region consisting of the meteorological subdivisions of Punjab, Haryana, west Rajasthan, east Rajasthan and west Madhya Pradesh. The results indicate a decreasing trend in the mean annual surface air temperature, which is mainly contributed by the south-west monsoon season (June through September), The mean annual and south-west monsoon season rainfall series over most parts of the region indicate a conspicuous increasing trend. The increasing trend is significantly marked for the subdivisions constituting the peripheral areas of the Rajasthan desert. These trends in rainfall and temperature are examined in relation to the changing land use pattern of the region due to extensive irrigation. Earlier findings of Winstanley (1973) reporting a decreasing trend in rainfall are found to be unacceptable due to the unrealistic assumptions of his study.
TL;DR: In this article, suspended sediment concentrations in the southeastern Yellow Sea range from 5 −100 mg l−1 at the surface and 5 −500 mg l − 1 at the bottom and the highest concentrations occur off the southwest tip of the Korean Peninsula and the lowest occur in the central part of the Korea Strait.
TL;DR: In this paper, the velocitypotential fields generated from the FGGE III-b horizontal winds of the European Centre for Medium Range Weather Forecasts were subjected to an empirical orthogonal function (EOF) analysis to extract the annual cycle and the 30-50 day mode of the divergent circulations.
Abstract: The velocity-potential fields generated from the FGGE III-b horizontal winds of the European Centre for Medium Range Weather Forecasts were subjected to an empirical orthogonal function (EOF) analysis to extract the annual cycle and the 30–50 day mode of the divergent circulations. We found that the Indian monsoon circulation is portrayed by the annual cycle of the divergent circulation and develops as a classical, giant sea-breeze model. On the other hand, this monsoon system is modulated by the planetary-scale 30–50 day low-frequency mode to establish an onset-active-break-revival-retreat life cycle. This modulation is accomplished through the following interaction process. The northeastward propagation of the planetary-scale 30–50 day mode over the Indian monsoon region induces transient local Hadley circulation. Through this type of circulation, the planetary-scale 30–50 day mode couples with and steers northward the low-level, 30-50 day monsoon troughs and ridges that originated around the e...
TL;DR: In this article, the authors identify and delineate large signals of climatic variation in the Asian monsoon region and try to understand the nature of transformation from one climate regime to another.
Abstract: The aim of this paper is to identify and delineate large signals of climatic variation in the Asian monsoon region and try to understand the nature of transformation from one climate regime to another. It is found that the summer monsoon over the Indian and western Pacific oceans shows distinct climatic regimes with changes occurring in the years around 1875, 1900, 1940 and 1960. The change of about 1900 is the largest one, which occurs in step with the variation of global oceanic climate pointed out by Fletcher, et al. (1982). The main characteristics of the transformation from one regime to another is an alternation of meridionality of monsoon current. The transformation occurs most strongly in the western Pacific convergence zone, where monsoon has strong interaction with the trade wind systems. The variability of monsoon rainfall over India and East China also exhibits some large signals which are synchronous with those of wind field over the ocean: the monsoon rainfall increases (decreases) during the “meridional monsoon period” (zonal monsoon period) over the ocean. It should be noted that the apparent decreasing of plum rains in East China since 1958 which is well known in China would be linked mainly with the sudden increasing ofU-component of SW monsoon over the South China Sea. Finally a kind of seesaw between Indian monsoon and East China monsoon with somewhat time-lag is discussed.
TL;DR: A comparison of isotopic data of groundwater with that of rainfall (during the period 1961-1978) indicates that groundwater in all the subbasins and at different depths is of meteoric origin having undergone direct evaporation and is genetically similar.
TL;DR: In this paper, the authors used regression models developed on 20-yr portions of the 1939-83 record to predict the summer monsoon rainfall anomalies of the 25 yr 1959-83.
Abstract: This study expands recent research into the predictability of Indian monsoon rainfall anomalies. In addition to the April latitude position of the 500 mb ridge over India, and Darwin pressure tendency, the May surface resultant wind speed in a strategic area of the jet axis over the western equatorial Indian Ocean (0–10°S, 45°–50°E) is used as predictor. Regression models developed on 20-yr portions of the 1939–83 record are employed to predict the summer monsoon rainfall anomalies of the 25 yr 1959–83. Correlation, root-mean-square error, bias, and absolute error are presented as measures of forecast performance on the “independent” dataset. It is found that the model constraint optimal for predictive purposes is to be ascertained empirically. “Updating” is not necessarily superior to the use of a fixed regression base period. Relationships between preseason indicators and monsoon rainfall were, strongest in the early and late portions of the 1939–83 record, and weakest in the 1950s and 1960s. A...
TL;DR: In this article, a prediction experiment designed to reveal the effects of this anomaly on the onset of the monsoon is described, and two important feedback loops are identified, one involving moisture-flux convergence and the other involving the surface fluxes of sensible and latent heat.
Abstract: At the time of the onset of the monsoon in June 1979 the sea surface temperatures in the eastern Arabian Sea were higher than normal. A prediction experiment designed to reveal the effects of this anomaly on the onset is described. This involves two 8-day forecasts made using the same model and the same initial conditions. They differ only in using different sea surface temperatures in the eastern Arabian Sea. A better prediction of the onset is obtained by using the anomalously high temperatures rather than the normal climatological values. In particular, the development of a tropical storm over the Arabian Sea, the strengthening of the Somali jet, and the northward movement of the rainfall over India are all better predicted. The mechanism of the onset in the model is discussed and two important feedback loops are identified, one involving moisture-flux convergence and the other involving the surface fluxes of sensible and latent heat. The most important factor in both loops is the release of latent heat over the Arabian Sea. A linear model is used to show that the onset may be thought of as a response to this heating. The roles of barotropic and baroclinic processes in the onset are also discussed.
TL;DR: In this paper, a model of direct and diffuse solar radiation on slopes of varying angle and aspect suggests that radiation differences within hilly terrain are maximized in the beginning of the dry season in the monsoon tropics.
Abstract: A model of direct and diffuse solar radiation on slopes of varying angle and aspect suggests that radiation differences within hilly terrain are maximized in the beginning of the dry season in the monsoon tropics. The differences between north and south facing slopes are greater than those found during the summer in the temperate zone. Within a study area near Mt. Bundey, Northern Territory, floristic and structural vegetational variability is closely related to June radiation as estimated by the model. However, the distribution patterns of monsoon thicket and eucalypt forest relate more to relative five protection than to the effects of incident radiation on temporal patterns of moisture availability. Within both major formations, site rockiness is an important influence on vegetation floristics and structure, both for five protection and through its influence on moisture availability.
TL;DR: In this article, a budget approach is used to study the physical and biological processes controlling the nutrient chemistry of the Red Sea outflow, which is modulated by the effects of monsoons in the Indian Ocean, especially in summer when the SW monsoon involves momentary subsurface inflow and surface outflow.
TL;DR: In this paper, the mean monthly surface thermal field over India during the premonsoon months March-May, based on mean monthly-temperature/minimum temperature/maximum temperature/temperature data from the network of 119 stations, was examined with the objective of locating significant predictor parameters for forecasting Indian monsoon rainfall.
Abstract: The mean monthly surface thermal field over India during the premonsoon months March-May, based on mean monthly-temperature/minimum-temperature/maximum-temperature data from the network of 119 stations, was examined with the objective of locating significant predictor parameters for forecasting Indian monsoon rainfall. The results of linear correlation analysis bring out three areas for which the relationships between Indian monsoon rainfalls and the area average of mean monthly minimum temperature for April or for May were found to be significant. The best correlation was found for the southern peninsular area, where the mean May minimum temperature is significantly related to the 500 mB April ridge, a tendency in the Southern Oscillation Index, and a tendency in eastern equatorial Pacific SST.
Abstract: A case study evaluating the predictive capability of an upper layer circulation model of the northwest Indian Ocean is presented The model is a nonlinear, reduced gravity model incorporating realistic boundary geometry and is forced by observed winds Model results for the fall of 1985 are compared with and evaluated against US Navy bathythermograph and NOAA satellite data collected during August–November 1985 An assessment is made of the model's ability to simulate correctly the circulation structure Ship wind observations are converted to wind stress for model forcing by a procedure developed by Legler and Navon (1988) The model is only moderately successful in reproducing the structure of the large, rather homogeneous pool of water located off the Arabian Peninsula in September However, the model behaves remarkably well in the dynamically active region around Socotra Major fronts and eddies frequently observed in the region during the transition period between the southwest and the northeast monsoon appear in the 1985 model results and compare well, both temporally and spatially, with the observational data Thus given accurate wind information, the model appears highly effective in dynamically active regions and demonstrates potential as a useful prognostic tool for evaluation of the Arabian Sea when real time winds become available
TL;DR: In this paper, the authors examined the interannual variability of the contributions of evaporation and moisture flux from the Southern Hemisphere towards the moisture transport across the west coast of India.
Abstract: In the present study interannual variability of the contributions of evaporation and moisture flux from the Southern Hemisphere towards the moisture transport across the west coast of India is examined. The mean rates of evaporation and precipitation over the Arabian Sea during the southwest monsoon season are 2.78 and 2.21 (×1010 tons/day, MKS, respectively). This suggests that the possible contribution from evaporation towards the moisture flux across the west coast of India is less significant. On a seasonal scale the ratio between cross-equatorial flux and the moisture transport across the west coast of India is found to be dominant irrespective of the monsoon activity. Only detailed information on evaporation and precipitation fields over the Arabian Sea under different phases of a monsoon could shed light on this problem.
TL;DR: The long-term variability of Indian summer monsoon rain-fall and related regional and global parameters are studied in this article, where the cubic spline is used as a digital filter to smooth the high frequency signals in the time series of the various parameters.
Abstract: The long-term variability of the Indian summer monsoon rain-fall and related regional and global parameters are studied. The cubic spline is used as a digital filter to smooth the high frequency signals in the time series of the various parameters. The length of the data series varies from 95 to 115 years during the period 1871-1985. The parameters studied within the monsoon system are: (a) monsoon rainfall of the country as a whole; (b) number of break-monsoon days during July and August; (c) number of storms/ depressions in Bay of Bengal and Arabian Sea during summer monsoon season; and (d) dates of onset of summer monsoon over South Kerala Coast. The parameters studied outside the monsoon system are: (a) the Wright’s Southern Oscillation Index (June-July-August); (b) the January mean Northern Hemispheric surface air temperature anomaly; and (c) the East-equatorial Pacific sea surface temperature anomaly.
TL;DR: The physical characteristics of the southwest branch of the North American monsoon system during the summer of 1979 are studied with the FGGE dataset as discussed by the authors, and mean monthly maps of vertically integrated water-vapor flux show the development of a low-level jet favoring the penetration, into western Mexico, of a cross-equatorial moist flow which originates over the southern Pacific.
Abstract: The physical characteristics of the southwest branch of the North American monsoon system during the summer of 1979 are studied with the FGGE dataset. The combined features such as the low pressure trough over northwestern Mexico, the penetration of the easterly flow from the Atlantic Ocean, and the intensification. of the anticyclonic gyre of the South Pacific, are responsible, during the summer, for a well established cross-equatorial surface air flow along the eastern tropical Pacific Ocean and western Mexico. Mean monthly maps of vertically integrated water-vapor flux show the development of a low-level jet favoring the penetration, into western Mexico, of a cross-equatorial moist flow which originates over the southern Pacific. It is shown that the South Pacific anticyclone gyre is an important feature which brings moist air along western Mexico. The mean monthly evolution of the net water-vapor flux divergence suggests a strong association with the precipitation pattern observed over Mexico.