Land Monsoon Research Articles

Characteristics of Diurnal and Seasonal Cycles in Global Monsoon Systems

In this paper, we characterize the climatological diurnal cycles over monsoon land and ocean regions, and seasonal cycles for six major monsoon systems around the world, from observations and outputs of the NASA Seasonal-to-Interannual Prediction Project (NSIPP) general circulation model outputs. Over monsoon land regions, the diurnal cycle has a pronounced late afternoon peak in rainfall and over the oceans a much weak diurnal signal with an early morning peak. The NSIPP model produces a daily peak in rainfall about 2–3 hours earlier than observed, possibly attributed to a cumulus parameterization which does not include cloud life cycle effects, and which lack detailed treatment of boundary layer processes. The seasonal cycles of all monsoon rain systems are controlled by an ITCZ and a subtropical and/or extratropical component due to the presence of contiguous large continental land mass. Strong climatological intraseasonal oscillations (CISO) are found in the monsoon systems of South Asia and East Asia, Australia, and South America, and to a lesser degree for West Africa and Mexico/North America. The NSIPP model captures the slow component seasonal component reasonably well, but the CISO’s are not well simulated. Analysis with reference to a new monsoon index shows that the major monsoon systems can be classified into three major groups (M1–3) according to the relative strength of continental vs. oceanic controls. East Asian and South Asian monsoons belong to a group (M1), where the continental influence is stronger than that from the ITCZ. The North America and South America monsoons show similar characteristics with the ITCZ influence slight stronger than continental influence (M2). The West Africa and Australia monsoons are found to be essentially ITCZ-monsoon systems (M3), with strong oceanic control, and limited poleward excursion of the monsoon rainbelt. We also find a clear trend associated with an increase in continentality for M3 monsoons, i.e., the West African and the Australian monsoons in the last two decades. We speculate that the former is linked to the partially recovery of the Sahel drought since the 1980’s.

Changes in global monsoon precipitation over the past 56 years

Changes in the global monsoon rainfall over land were examined using four sets of rain‐gauge precipitation data sets compiled for the period of 1948–2003 by climate diagnostic groups around the world. Here, we define a global monsoon rain domain according to annual precipitation range, using simple objective criteria; then, we propose metrics for quantifying the intensity of the global monsoon precipitation. The results suggest an overall weakening of the global land monsoon precipitation in the last 56 years, primarily due to weakening of the summer monsoon rainfall in the Northern Hemisphere. However, since 1980, the global land monsoon rainfall has seen no significant trend, which contrasts with the rapid intensification of global warming during the same period. Meanwhile the oceanic monsoon precipitation shows an increasing trend after 1980. The results provide a rigorous test for climate models that will be used in future climate‐change assessment.

Estimation of the Exchange Coefficient of Heat During Low Wind Convective Conditions

For the first time, the exchange coefficient of heat CH has been estimated from eddy correlation of velocity and virtual temperature fluctuations using sonic anemometer measurements made at low wind speeds over the monsoon land atJodhpur (26°18' N, 73°04' E), a semi arid station. It shows strong dependence on wind speed, increasing rapidly with decreasing wind speed, and scales according to a power law CH = 0.025U10 -0.7 (where U10 is the mean wind speed at 10-m height). A similar but more rapid increase in the drag coefficient CDhas already been reported in an earlier study. Low winds (<4 m s-1) are associated with both near neutral and strong unstable situations. It is noted that CH increases with increasing instability. The present observations best describe a low wind convective regime as revealed in the scaling behaviour of drag, sensible heat flux and the non-dimensional temperature gradient. Neutral drag and heat cofficients,corrected using Monin–Obukhov (M–O) theory, show a more uniform behaviour at low wind speeds in convective conditions, when compared with the observed coefficients discussed in a coming paper. At low wind convective conditions, M-O theory is unable to capture the observed linear dependence of drag on wind speed, unlike during forced convections. The non-dimensional shear inferred from the present data shows noticeable deviations from Businger's formulation, a forced convection similarity. Heat flux is insensitive to drag associated with weak winds superposed on true free convection. With heat flux as the primary variable, definition of new velocity scales leads to a new drag parameterization scheme at low wind speeds during convective conditionsdiscussed in a coming paper.

Relationship between land cover and monsoon interannual variations in east Asia

Asian monsoon have multiple forms of variations such as seasonal variation, intra-seasonal variation, interannual variation, etc. The interannual variations have not only yearly variations but also variations among several years. In general, the yearly variations are described with winter temperature and summer precipitation, and the variations among several years are reflected by circulation of ENSO events. In this study, at first, we analyze the relationship between land cover and interannual monsoon variations represented by precipitation changes using Singular Value Decomposition method based on the time series precipitation data and 8km NOAA AVHRR NDVI data covering 1982 to 1993 in east Asia. Furthermore, after confirmation and reclassification of ENSO events which are recognized as the strong signal of several year monsoon variation, using the same time series NDVI data during 1982 to 1993 in east Asia, we make a Principle Component Analysis and analyzed the correlation of the 7th component eigenvectors and Southern Oscillation Index (SOI) that indicates the characteristic of ENSO events, and summed up the temporal-spatial distribution features of east Asian land cover’s inter-annual variations that are being driven by changes of ENSO events.

BOOK REVIEWS

Book Review in this ArticlesAlfarabi's Book of Reliaon and Related Texts. Arabic Texts, edited with introduction and notes by Muhsin Mahdi.The Arabic Language: Its Role in History. By Anwar G. Chejne.The Shadow of the Crescent: The Renaissance Image of the Turk (1453–1517). By Robert Schwoebel.Islam, Europe and Empire. By Norman Daniel.Madkhal ilã '1–Hiwãr al‐Islãm? al‐Masihi By al‐Ustãdh al‐Haddãd.The Monsoon lands of Asia. By R. R. RawsaTha Histories ol Nishpur. Edited by Richard N. Frye.The Ancient Near East: Supplementary Texts and Pictures Relating to the Old Testament. Edited by James B. Pritchard.

The Monsoon Lands of Asia

The Monsoon Lands of Asia

The Monsoon Lands of Asia

The Monsoon Lands of Asia

Education and Nation-Building in Laos

As one of the new states emerging from a colonial past, the Southeast Asian Kingdom of Laos, like a number of African and Middle Eastern states, does not fit in with concepts of the nation state. They possess something less than Emerson's characteristics of an ideal nation, i.e. a fixed geographic boundary, a cohesive ideology, a common ethnic group, a unifying economic structure, and a shared history and culture.1 Yet this small land-locked country, certainly outwardly the least-favored part of the former French Indo-Chinese complex, lacks all of these qualities with exception of a fixed geographic boundary to a marked degree. These indicators of unity and common experience have not increased greatly in degree since 1949, when independence from France was obtained. By way of illustration, a survey of the late 1950's demonstrated that the name of the late king of Luang Prabang, who had ruled for 56 years, was known by a relatively small proportion of the population.2 A public opinion poll conducted in the mid-1950's suggested that at that time less than half the population knew the name of their country.3 This monsoon land of varied climate and terrain ranges from the wet rice-growing valley of the Mekong River to the mountainous provinces of the north and east inhabited by tribally organized slashand-burn agriculturalists, ethnically distinct from the politically dominant valley-dwelling Lao. The population is overwhelmingly rural, with over 90 per cent of Laos' roughly 2,500,000 people estimated to rely on agriculture for a living. Industrial or commercial development has been virtually negligible, with what exists dependent primarily upon foreign aid. Cities are little more than small towns, the largest being Vientiane, the seat of government, which reported a population of 68,000 in 1959; the royal capital, Luang Prabang, had about 11,000; only three others, all provincial capitals, had populations in excess of 5,000. Transportation difficulties, which make overland travel difficult among many of the 16 provinces, help to explain the weakness of French colonial penetration into Laos as compared with Cambodia and Vietnam. Similar transportation and communication problems impede the Royal Lao Government's (RLG) effectiveness in implementing any sort of program on a national basis. Most provinces are cut off from the capital city, and small planes are the only means of conveyance. While the river system provides a natural transportation network, it is effective only in reaching the valley-dwelling Lao. In light of these and other factors, Laos is characterized by a low economic productivity aggravated almost since the nation's inception by a heavy military burden; despite considerable investments of foreign aid, principally from the United States and France, there continue to be serious doubts of the country's economic viability under the present circumstances. Not the least among the obstacles to national development is the fact that Laos has the highest rate of illiteracy in Southeast Asia, with estimates ranging between 80 and 85 per cent.4

Reviews of books

Reviews of books

The Monsoon Lands of Asia

The Monsoon Lands of Asia

The Monsoon Lands of Asia

The Monsoon Lands of Asia

The Monsoon Lands of Asia.

The Monsoon Lands of Asia.

The Twenty-Five-Hundredth Anniversary of the Buddha

The full moon in May is the occasion of the greatest festival of the year in the Buddhist world, it being the triple anniversary of the birth of Sakyamuni, of his ascent to the omniscience of a Buddha, and of his final extinction in Parinirvana. Ceylon and the countries of southeast Asia, which adopted the Singhalese Buddhism in the thirteenth century—Burma, Thailand, Cambodia, and Laos—are monsoon lands where the month of May coincides with the beginnings of the rains, thus signaling great rejoicing exemplified by offerings to the monks, recitals of prayers, and nocturnal circumambulations of the temples by the faithful torchbearers.

The Political Economy of Population

THE author is the personification of energy and versatility as he pours out book after book devoted to the setting forth of the facts, and inferences, of human ecology. For us, in Europe, he has the added value that he knows a great deal about us and writes in our language, a rather American English, while at the same time speaking from the point of view of a member of the huge concentration of half mankind on the relatively small space of the Monsoon Lands. Mukerjee continually reiterates that political economy, biology, genetics, politics and sociology all fall short because they look at selected elements and neglect others which are vital for the understanding of a composite social process that, in his view, may claim success if it maintains a balance of activities and population that can go on indefinitely. The solution of the population problem in Europe lies neither in the sacrifice of children to the pursuit of a highly artificial standard nor in the sacrifice of personal values to the prestige of the State ; he seeks, rather, a balance. Perhaps he is not explicit enough concerning the mentality apt to spread when decline of population is imminent ; we Europeans know its difficulties only too well from the case of France, 1923-1940. The Political Economy of Population By Prof. Radhakamal Mukerjee. (Lucknow University Studies, Faculty of Arts.) Pp. xiv + 467. (London, Bombay, New York and Toronto: Longmans, Green and Co., Ltd., n.d.) 7s. 6d.

Bauxite: a Treatise discussing in Detail the Origin, Constitution, known Occurrences, and Commercial Uses of Bauxite: and including Particulars regarding the Present Conditions of the Aluminium Industry and the Pecutiar a Importance of Cryolite in the Extraction of Aluminium from Bauxite

WITH the increasing popularity of the metal aluminium, increasing interest is being taken in its principal ore, bauxite, and Dr. Fox has opportunely provided a trustworthy and comprehensive treatise on the occurrence and uses of this substance. lie distinguishes two principal modes of origin, the terra rosa (sic) type representing the insoluble residue of great masses of soluble limestone or dolomite, and the lateritic type resulting from the decomposition in situ of original aluminous rock. The former occurs mainly in the Mediterranean region of Europe, and the latter in the tropical monsoon lands of Asia, Africa, and America.