scholarly journals Meteorological sub-divisions of India : Assessment of coherence, homogeneity and recommended redelineation

MAUSAM ◽  
2021 ◽  
Vol 71 (4) ◽  
pp. 585-604
Author(s):  
KULKARNI ASHWINI ◽  
GUHATHAKURTA PULAK ◽  
PATWARDHAN SAVITA ◽  
GADGIL SULOCHANA
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Rainfall Anomaly ◽  
Seasonal Rainfall ◽  
Western Coast ◽  
Clustering Method ◽  
Station Network ◽  
Average Rainfall ◽  
Measure Of Similarity ◽  
Different Time Scales

The data on mean rainfall and mean rainfall anomaly of the meteorological sub-divisions of India, on different time-scales, is extensively used for monitoring the progress of the monsoon as well as applications and research.  As such, it is important to ensure that the sub-divisional means are meaningful representations of the rainfall and the rainfall anomaly at districts/stations within the sub-division. Hence, the criteria to be satisfied for an appropriate delineation of a meteorological sub-division are high levels of coherence and homogeneity. In this paper we present an  assessment of  the coherence and homogeneity of the current meteorological sub-divisions, for rainfall on the seasonal scale, by analysis of monthly district average rainfall for the period 1901-2015 during the summer monsoon for all the states, except Tamil Nadu for which June-December data are considered.   Since, earlier studies have shown that some of the sub-divisions of Karnataka and Maharashtra are neither coherent nor homogeneous, the problem of redelineation of the sub-divisions of these states is first addressed.  We have assumed that the number of coherent zones in a state is the same as the number of current sub-divisions. Identification of coherent zones is achieved by successive application of the K-means (KM) clustering method to the seasonal rainfall of the districts, considering correlation of seasonal rainfall between districts as a measure of similarity. For these two states we find that some of the districts are not coherent and homogeneous. So we have repeated the exercise with analysis of a dense station network. The coherent zones identified from analysis of district data as well as station data, are found to be homogeneous as well and we have recommended that they become the new sub-divisions of the states.  The new sub-divisions suggested for Karnataka, which are coherent and homogeneous, are: (i) Karnataka Western coast and Ghats (which includes districts/stations in the current sub-division of Coastal Karnataka as well as some from the sub-divisions of interior Karnataka) (ii) Karnataka northern plateau and (iii) Karnataka southern plateau. Of the current sub-divisions of Maharashtra, Marathwada and Vidarbha satisfy the criteria of coherence and homogeneity and can be retained as such. The current Madhya Maharashtra sub-division does not satisfy the criteria of coherence and homogeneity. We have derived a modified version of Madhya Maharashtra by allocation of some districts/stations of Western Ghats from the existing sub-division of Madhya Maharashtra to the existing sub-division of Konkan and Goa to generate a modified version of Konkan and Goa.  These modified versions are coherent and homogeneous. Thus the suggested sub-divisions of Maharashtra are (i) modified version of Konkan and Goa (which could have been renamed as Konkan, Ghats  and Goa but we have retained the old name) and (ii) modified version of Madhya Maharashtra, along with the current sub-divisions of (iii) Marathwada  and (iv) Vidarbha. We have shown that the sub-divisions of all the other states of mainland India, are homogeneous and reasonably coherent and recommend that they should be retained as such.

scholarly journals Development and Assessment of Localized Seasonal Rainfall Prediction Models: Mapping and Characterizing Rift Valley Fever Hotspot Areas in the Southern and Southeastern Ethiopia

2018 ◽  
Vol 11 (5) ◽  
pp. 102
Author(s):  
Ephrem Weledekidane
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Large Scale ◽  
Prediction Models ◽  
Rainfall Anomaly ◽  
Seasonal Rainfall ◽  
Valley Fever ◽  
Average Rainfall ◽  
Early Indicators

Rift Valley Fever disease has been recognized as being among permanent threats for the sustainability of livestock production in Ethiopia, owing to shared boarders with RVF endemic countries in East Africa. Above-normal and widespread rainfall have outweighed as immediate risk factor that facilitated historical outbreaks of the disease in the East Africa. The objective of the present study, thus, was to develop prospective localized seasonal rainfall anomaly prediction models, and assess their skills as early indicators to map high risk localized rift valley fever disease outbreak areas (hotspots) over the southern and southeastern part of Ethiopia. 21 years of daily rainfall data; for five meteorological stations, was employed in diagnosing existences of any anomalous patterns of rainfall, along with a cumulative rainfall analysis to determine if there were ideal conditions for potential flooding. The results indicated that rainfall in the region is highly variable; with non-significant trends, and attributed to be the results of the effects of large-scale climatic-teleconnection. The moderate to strong positive correlations found between the regional average rainfall and large scale teleconnection variables (r ≥ 0.48), indicated some potentials for early prediction of seasonal patterns of rainfall. Accordingly, models developed, based on the regional average rainfall and emerging developments of El Niño/Southern Oscillation and other regional climate forcings, showed maximum skills (ROC scores ≥ 0.7) and moderate reliability. Deterministically, most of the positive rainfall anomaly patterns, corresponding to El Niño years, were portrayed with some skills. The study demonstrated that localized climate prediction models are invaluable as early indicators to skillfully map climatically potential RVF hotspot areas.

AVIAN DIVERSITY AND ITS ABUNDANCE IN THE KETHI VALLEY AREAS,THE NILGIRIS, WESTERN GHATS, TAMIL NADU.

2017 ◽  
Vol 5 (8) ◽  
pp. 781-788
Author(s):  
G Kalaiyarasi ◽  
◽  
D Jayabalan ◽  
C Rameshkumar ◽  
C Subramanian ◽  
...  
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Avian Diversity ◽  
The Nilgiris

scholarly journals Ramalina obtusata, a new lichen flora addition to Southern Western Ghats, Tamil Nadu, India

2021 ◽  
Vol 6 ◽  
pp. 100140
Author(s):  
Murugan Mariraj ◽  
Muthu Shenbagam ◽  
Rajendran Kalidoss ◽  
Ponnusamy Ponmurugan
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Southern Western Ghats ◽  
Lichen Flora

scholarly journals Distribution and habitat associations of the Critically Endangered frog Walkerana phrynoderma (Anura: Ranixalidae), with an assessment of potential threats, abundance, and morphology

2018 ◽  
Vol 17 (1) ◽  
pp. 21
Author(s):  
Arun Kanagavel ◽  
Sethu Parvathy ◽  
Abhiijth P. Chundakatil ◽  
Neelesh Dahanukar ◽  
Benjamin Tapley
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Habitat Associations ◽  
Critically Endangered ◽  
Suitable Habitat ◽  
Time Activity ◽  
Western Ghats Of India ◽  
Pesticide Runoff ◽  
The Impact ◽  
The Western Ghats

Distribution and habitat associations of the Critically Endangered frog Walkerana phrynoderma (Anura: Ranixalidae), with an assessment of potential threats, abundance, and morphology. Little is known about Walkerana phrynoderma, a frog endemic to the Anamalai Hills of the Western Ghats of India. Baseline information (i.e., distribution, threats, habitat characteristics, activity patterns, and relative abundance) is provided for this species, with the aim of improving our understanding of the status of the species in the wild. Visual-encounter, transect, and time-activity budget surveys were conducted in and around the Anamalai Hills of the Western Ghats. The frog skin was swabbed to determine the presence/absence of Batrachochytrium dendrobatidis, and habitat and environmental characteristics were recorded at sites where W. phrynoderma was found. These data were compared with those of sites apparently lacking this species that had suitable habitat. Walkerana phrynoderma is restricted to evergreen forests between 1300 and 1700 m a.s.l. in the Anamalai Tiger Reserve and at Munnar; thus, its range was extended from the state of Tamil Nadu to the adjoining state of Kerala. Pesticide runoff and human disturbance are the most severe threats to the species; B. dendrobatidis was not detected. This nocturnal anuran prefers forest edges and is associated with well-shaded forest foors in cool areas near freshwater streams. Walkerana phrynoderma is rarely encountered whereas its congener, W. leptodactyla, is more common. The impact of anthropogenic disturbances, especially waste disposal and development of tourism infrastructure, should be evaluated. The land that is owned by the Forest Department peripheral to the protected areas could be designated as eco-sensitive sites to prevent changes in land use that could have an adverse effect on W. phrynoderma.

Anti-microbial and Anti-oxidant Properties of Solvent Extract of Lichen Species Collected from Kodaikanal Hills, Western Ghats of Tamil Nadu

Phytomedicine ◽  
2020 ◽  
pp. 53-61 ◽  
Author(s):  
R. Kalidoss ◽  
M. Mariraj ◽  
M. Shenbagam ◽  
J. Merlin Seles ◽  
K. Arun Prasath ◽  
...  
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Lichen Species ◽  
Solvent Extract ◽  
Anti Oxidant

scholarly journals REPRODUCTIVE BIOLOGY OF GNETUM LATIFOLIUM BLUME (GNETALES) IN TAMIL NADU

2016 ◽  
Vol 3 (2) ◽  
pp. 75-78
Author(s):  
Karupusamy S
Keyword(s):  
Reproductive Biology ◽  
Western Ghats ◽  
Tamil Nadu ◽  
Low Frequency ◽  
Seed Maturation ◽  
Male Population ◽  
Dioecious Plants ◽  
Very Low Frequency ◽  
Forest Sites

The reproductive biology of Gnetum latifolium Blume studied in four different forest sites of Tamil Nadu. G. latifolium reported to have dioecious plants with less number male population in all the selected areas. Entamophilous cues observed with common anaemophily and pollinator may be flies. Pollination dropsare also reported in young ovules. The seed maturation and germination frequency observed with very low frequency in all the selected population whereas in high number of abortive ovules reported in Western Ghats.

scholarly journals PHYTOSOCIOLOGICAL ANALYSIS OF THE MEDICINAL PLANT SPECIES, THALICTRUM JAVANICUM BLUME IN THOTTABETTA, NILGIRIS, THE WESTERN GHATS

2015 ◽  
Vol 2 (1) ◽  
pp. 56-62
Author(s):  
Abinaya G ◽  
Paulsamy S
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Degree Of Dominance ◽  
The Family ◽  
Qualitative Characters ◽  
The Nilgiris ◽  
The Western Ghats ◽  
Study Species ◽  
Phytosociological Study

Phytosociological study is the most essential in any community to know its structure and organization. The various qualitative characters obtained are used to determine the level of distribution, numerical strength and degree of dominance exhibited by the constituent species in the community. Thalictrum javanicum belongs to the family Ranunculaceae family, it is medium sized erect herb, found in the temperate Himalayas from Kasmir to Sikkim in Khasi hills, and Kodaikanal and Nilgiri hills of Western Ghats in Tamil Nadu, India. At global level, it is generally distributed in the hilly tracts of India, Srilanka, China and Java at the altitude of around 2400 m above msl. The present study was undertaken in Thottabetta , the Nilgiris by sampling using belt transects of 10x1000m size which further divided into 100 segments each which 10x10m size. The total number of species encountered in the study area is 45 which includes 5 grasses and 40 forbs. The quantitative ecological characters of the study species, T. javanicum is a detailed below: frequency 11%, abundance 3.82 individuals/m2, density 0.42 individuals/m2, basal cover 172.20/mm2/ m2, relative frequency 0.55% and relative density 0.08%, relative dominance 0.16%. Based on the ecological attributes it is determined that the species, T. javanicum is less perpetuated in the community studied. Hence, further studies on the determination of propagation strategies for population enhancement and conservationof wilds are suggested.

scholarly journals A Survey of the genus Theretra Hubner, 1819 (Lepidoptera Sphingidae) from Kodaikanal Hills (Western Ghats), Tamil Nadu, India

2019 ◽  
Vol 6 (1) ◽  
pp. 253-262
Author(s):  
Pratheesh Mathew ◽  
Kuppusamy Sivasankaran ◽  
Sekar Anand ◽  
Savarimuthu Ignacimuthu
Keyword(s):  
Western Ghats ◽  
Tamil Nadu
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