A comparative study of summer monsoon features over India during 1987 to 1997

In this paper comparative study of characteristic features of summer monsoon, viz. onset and withdrawal, synoptic situations causing heavy rainfall, average seasonal monsoon rainfall over the country and floods generated in Indian rivers in each monsoon season has been made on the basis of 11-years' data (1987 to 1997). It is shown that each monsoon season is quite unique in its behaviour and no two monsoons are alike

Study of rainfalls recorded at the Cherrapunji Observatory

The maximum rainfalls recorded at the Cherrapunji Observatory raingauge during various periods within the 57 years from 1903 to 1959 have been studied and the equation of the enveloping line has found to be R = 49 D0.485 where R is the rainfall in inches and D is duration in days. One-day maximum rainfalls for different periods from two to 100 years have also been worked out and the 100-year value has been found to be 2.1 times the 2-year value. The daily probable maximum precipitation (PMP), estimated by the Hershfield technique, is 78 in. A study of annual and monsoon rainfalls did not show any general linear trend but there was a gradual increase in amounts from 1944 to 1954

Should extreme precipitation recorded over a long period of time be considered as an estimate of PMP?

The World Meteorological Organization's Manual (1986) has given very elaborate procedures for the estimation of Probable Maximum Precipitation for the design of hydraulic structures where no risks can be taken. These are based upon the assumption that severe meteorological factors like rainstorm mechanism and extreme moisture charge, which when combined together will produce PMP. McGregor (1998) and others feel that in nature, extreme meteorological factors may never combine, as such PMP depths obtained by the above procedures are only hypothetical. It has been suggested that actual extreme values of precipitation obtained over the globe based upon a long period of data may be considered as PMP. In view of this, extreme values of precipitation obtained over India during the last 125 years have been picked out from the data and their values for point stations as well as for different standard areas and durations (i.e. Depth-Area-Duration (DAD) statistics) have been given in this paper and may be considered as estimates of PMP for different regions of the country. © The International Journal of Meteorology

Highest ever 24-hours rainfall value

Jenamani et al.1 have reported that ‘Kasauli’ Himachal Pradesh) recorded maximum one-day rainfall of 99.6 cm on 17–18 June 1899. We have checked this with original records of the India Meteorological Department (Pune) and found that the highest rainfall given for Kasauli station is wron

The rainstorm ( Machhu valley)which caused the Morvi dam disaster in August 1979.

On 11 August 1979, the Machhu-2 earth dam, situated about 6 km upstream of the town of Morvi in the Saurashtra region of India, collapsed under the onrush of an unprecedented volume of water. An 8–10 m high flood wave rolled down Machhu valley, entirely submerging Morvi and nearby villages. This flash flood caused the deaths of thousands of people and totally destroyed urban and rural property downstream of the dam. The heavy rainfall of August 1979 over and around the Machhu basin has been analysed by both depth-area-duration and depth-duration methods. Important aspects of heavy rainfall distribution such as: analysis of past severe rainstorms, maximum point rainfall of different return periods, and probable maximum precipitation, were also studied. This study has shown that this event was not the most severe rainstorm in this region. Possibly, the antecedent conditions of the Machhu basin played a significant role in generating the flood volume which caused the earth flanks of the dam to give way

Extended Fermion Representation of Multi-Charge 1/2-BPS Operators in AdS/CFT -- Towards Field Theory of D-Branes --

We extend the fermion representation of single-charge 1/2-BPS operators in the four-dimensional N=4 super Yang-Mills theory to general (multi-charge) 1/2-BPS operators such that all six directions of scalar fields play roles on an equal footing. This enables us to construct a field-theorectic representation for a second-quantized system of spherical D3-branes in the 1/2-BPS sector. The Fock space of D3-branes is characterized by a novel exclusion principle (called `Dexclusion' principle), and also by a nonlocality which is consistent with the spacetime uncertainty relation. The Dexclusion principle is realized by composites of two operators, obeying the usual canonical anticommutation relation and the Cuntz algebra, respectively. The nonlocality appears as a consequence of a superselction rule associated with a symmetry which is related to the scale invariance of the super Yang-Mills theory. The entropy of the so-called superstars, with multiple charges, which have been proposed to be geometries corresponding to the condensation of giant gravitons is discussed from our viewpoint and is argued to be consistent with the Dexclusion principle. Our construction may be regarded as a first step towards a possible new framework of general D-brane field theory.Comment: 43 pages, 4 figures; version 2, corrected typos and added reference