Southwest Indian Research Articles

Satellite-determined cloudiness in the tropics in relation to large scale flow patterns Pt. II. Case-studies of developments outside the Indian southwest monsoon region

The paper contains the results of 4 case studies of satellite observations of clouds especially over se-areas in the tropics, in relation to monthly mean large-scale flow-patterns during the period June to September 1965. Three of the case-studies relate to the southern hemisphere in the region of westerlies and one to the northern hemisphere in the region of easterlies. These studies have shown that there are close associations between satellite-determined cloudiness and certain specifie types of flow patterns at the 700, 500 and 300-mb levels. The observed quasi-empirical relationships would be useful to the forecaster in his day-to-day predictions, especially for sea areas wherefrom he may not have any cloud or rainfall observations at the time of forecasting.
 

Satellite-determined cloudiness in the tropics In relation to large scale flow patterns Pt. I: Studies of different phases of the Indian southwest monsoon

The mean cloudiness in 21-degree grid squares over the area extending from 30°N to 20°S and from 55°E to 100°E were computed from daily satellite observations of clouds for specific periods associated with {a) late U K and normal onset of the monsoon, {b) break in "the monsoon and (c) early and normal retreat of the monsoon in the years 1965,1966 and 1967. The isopleths of mean cloudiness in these specific periods were studied particularly in relation point to the mean large scale flow patterns over Asia and the neighbouring countries at the 500 and 300-mb levels. The daily avail- 500,300 and 200-mb charts during the retreating phases of the monsoon were also examined. The regions of development of maxima and minima of cloudiness have been discussed with reference to the large scale flow patterns and the L 0 lacunae in our present knowledge of the mechanism of these developments pointed out. The low pressure waves which, moved from east to west across the extreme south of peninsular India during the break period in August 1965, have Delhi for also been discussed in detail with reference to the isopleths of cloudiness and anomalies of rainfall. The significance of the observed persistent heavy cloudiness from 5°N to 5°Sacross the equator and the extension of the heavy cloudiness B in further to the south in the southern hemisphere during the break in the monsoon have also been discussed.

Some aspects of broad-scale cloud distribution over Indian Ocean during Indian Southwest Monsoon Season

Satellite cloud information and ship data collected during the I.I.O.E. period are utilised to study the broad-scale cloud distribution over Indian Ocean during Indian southwest monsoon season, Examination of a large number of satellite observed cloud patterns over the Indian Ocean during the southwest monsoon season reveals some aspects of broad-scale cloud features. These features are looked in to in relation to the low level wind field and an attempt is made to establish a linkage between the cloud field and the wind field. Analysis of I.I.O.E. ship data collection also lends support to the conclusions derived from satellite data. Certain features of equatorial cloud distribution are also pointed out. The difference in the cloud distribution between tropical Atlantic and Pacific and tropical Indian Ocean is adduced to the differences in sea surface temperature distribution as well as geographical distribution of land and sea areas.

ON THE MAINTENANCE OF THE MEAN ZONAL MOTION IN THE INDIAN SUMMER MONSOON

The maintenance of the westerlies in the lower troposphere and the easterlies in the upper troposphere in the Indian southwest monsoon is studied by considering the angular momentum balance in the region. The main source term for the zonal angular momentum is the Coriolis or the Ω-transport term. This term contributes enough to maintain the lower tropospheric westerlies against friction. The zonal pressure gradient term and the mountain torque are of a smaller magnitude. The flux divergence at the boundaries is small in the lower troposphere; it is large in the upper troposphere and serves to export the easterly momentum produced in the region. Thus, it is concluded that the mean meridional circulation (which is direct) mainly contributes to the maintenance of the mean zonal motion. Actually there is divergence of eddy flux of momentum from the region of maximum zonal winds. The mean meridional circulation releases kinetic energy of the same order of magnitude as the release by the mean winter meridional cell over an equal area.

On a remarkable case of dynamical and physical interaction between middle and low latitude weather systems over Iran

This paper contains the results of a detailed study of a wet spell over and near north Iran during the second half of July 1956, which contributed to the severe floods in that country during that month. The daily sea level, 850, 700, 500 and 300-mb level charts for Asia, Eastern Europe and the adjoining areas for the period of the wet spell, the mean 700 and 500-mb charts for the month of July 1956 as a whole and the mean sea level and 500-mb charts for the period of the wet spell only, along with the relevant thermodynamic diagrams have been studied. On the basis of this study, the broad conclusion is reached that the rainfall in Iran during the wet spell even over regions as far north as the Caspian Sea was fundamentally due to the extension of the Indian southwest monsoon into those regions during a month when the monsoon was abnormally active over the whole of India. This development was associated with an unusually pronounced Tibetan High shifting far to the west of its usual position. This abnormal situation resulted in the monsoon easterlies in the lower troposphere being drawn into Iran and the troughs in the middle and upper troposphere which were basically part of closed cyclonic systems in the higher middle latitudes, being blocked and thereby remaining quasi-stationary just to the west of the Caspian Sea. The wave patterns in the upper tropospheric middle latitude westerlies under these conditions caused high level divergence over Iran which provided the main dynamical mechanism for lifting the monsoon air over that country. In addition, on the two days of peak-activity during the wet spell, colder air from the middle latitudes seemed to have undercut the warm humid monsoon air on the southern shores of the Caspian Sea and provided a secondary physical mechanism for lifting the monsoon air on those days. Thus we had in July 1956 the remarkable spectacle of monsoon rainfall over and near North Iran caused by dynamical and physical interaction between middle and low latitude weather systems over that country.

ART AND FOLKLORE:Southwest Indian Painting.Clara Lee Tanner

ART AND FOLKLORE:Southwest Indian Painting.Clara Lee Tanner

An Anthropologist Looks at History

Research Article| August 01 1957 An Anthropologist Looks at History A. L. Kroeber A. L. Kroeber Search for other works by this author on: This Site PubMed Google Scholar Pacific Historical Review (1957) 26 (3): 281–287. https://doi.org/10.2307/3636217 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation A. L. Kroeber; An Anthropologist Looks at History. Pacific Historical Review 1 August 1957; 26 (3): 281–287. doi: https://doi.org/10.2307/3636217 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentPacific Historical Review Search This content is only available via PDF. Article PDF first page preview Close Modal You do not currently have access to this content.

XLIX.—New species of South American and West Indian Chrysomelidæ (Halticinæ, Col.)

XLIX.—<i>New species of South American and West Indian</i> Chrysomelidæ (Halticinæ, <i>Col.</i>)

Evolution of Population and Dwelling in the Indian Southwest

Journal Article Evolution of Population and Dwelling in the Indian Southwest Get access Etienne B. Renaud Etienne B. Renaud Search for other works by this author on: Oxford Academic Google Scholar Social Forces, Volume 7, Issue 2, December 1928, Pages 263–270, https://doi.org/10.2307/2570153 Published: 01 December 1928