scholarly journals Variability of south west monsoon rainfall in West Bengal : An application of principal component analysis

MAUSAM ◽  
2021 ◽  
Vol 65 (4) ◽  
Author(s):  
PIJUSH BASAK
Keyword(s):  
Principal Component Analysis ◽  
West Bengal ◽  
Monsoon Rainfall ◽  
Principal Component ◽  
Component Analysis ◽  
Southwest Monsoon ◽  
Spatial And Temporal Variability ◽  
Annual Variations ◽  
South West Monsoon ◽  
Southwest Monsoon Rainfall

The principal component analysis is utilized to understand the spatial and temporal variability of monsoonal rainfall. The southwest monsoon rainfall data of West Bengal, situated over 21 stations widely spread over the state, has been analyzed for a period of 60 years for inter-annual variations. A coherent subset of 8 north and 13 south stations has been studied separately to produce statistically significant inter-annual signals. It is observed that the above/below transition is quite significant both for station rainfalls and principal components for state-wise and coherent zone analysis.

scholarly journals Southwest monsoon rainfall in Assam: An application of principal component analysis for understanding of variability

MAUSAM ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 357-366
Author(s):  
PIJUSH BASAK
Keyword(s):  
Principal Component Analysis ◽  
Principal Components ◽  
Temporal Variability ◽  
Monsoon Rainfall ◽  
Principal Component ◽  
Component Analysis ◽  
Southwest Monsoon ◽  
The State ◽  
Spatial And Temporal Variability ◽  
Southwest Monsoon Rainfall

The principal component analysis (PCA) is applied to understand the spatial and temporal variability of monsoonal rainfall in the state Assam in India. The Southwest Monsoon (SWM) rainfall data over 12 widely spread stations located over the state has been analyzed for a period of 60 years for understanding variability. A statistically significant trend and a above/below transition signal has been observed for a few stations and the corresponding principal components (PCs). Coherent regions of Northern and Southern Assam have been identified through PCA to bring out the possible significant signals. It is observed that some of PCs for state-wise and coherent regions have positive or negative trend and significant above/below transition.    

scholarly journals Spatial and temporal variability of precipitation and drought in Portugal

2012 ◽  
Vol 12 (5) ◽  
pp. 1493-1501 ◽  
Author(s):  
D. S. Martins ◽  
T. Raziei ◽  
A. A. Paulo ◽  
L. S. Pereira
Keyword(s):  
Principal Component Analysis ◽  
Standardized Precipitation Index ◽  
Principal Component ◽  
Component Analysis ◽  
Maximum Temperature ◽  
Drought Indices ◽  
Drought Severity ◽  
Spatial And Temporal Variability ◽  
Monthly Precipitation ◽  
Precipitation Regimes

Abstract. The spatial variability of precipitation and drought are investigated for Portugal using monthly precipitation from 74 stations and minimum and maximum temperature from 27 stations, covering the common period of 1941–2006. Seasonal precipitation and the corresponding percentages in the year, as well as the precipitation concentration index (PCI), was computed for all 74 stations and then used as an input matrix for an R-mode principal component analysis to identify the precipitation patterns. The standardized precipitation index at 3 and 12 month time scales were computed for all stations, whereas the Palmer Drought Severity Index (PDSI) and the modified PDSI for Mediterranean conditions (MedPDSI) were computed for the stations with temperature data. The spatial patterns of drought over Portugal were identified by applying the S-mode principal component analysis coupled with varimax rotation to the drought indices matrices. The result revealed two distinct sub-regions in the country relative to both precipitation regimes and drought variability. The analysis of time variability of the PC scores of all drought indices allowed verifying that there is no linear trend indicating drought aggravation or decrease. In addition, the analysis shows that results for SPI-3, SPI-12, PDSI and MedPDSI are coherent among them.

scholarly journals DAKSHIN BHARTIYA PADHAR PAR HONE WALI MONSOON WARSHA KA PRADHAN AVYAV VISHLESHAN

MAUSAM ◽  
2021 ◽  
Vol 48 (1) ◽  
pp. 77-82
Author(s):  
O.P. SINGH
Keyword(s):  
Principal Components ◽  
Andhra Pradesh ◽  
Monsoon Rainfall ◽  
Principal Component ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Northeast Monsoon Rainfall ◽  
Total Variability ◽  
Southwest Monsoon Rainfall ◽  
The Impact

 The result of the Principal Component Analysis of southwest and northeast monsoon rainfall on the southern India plateau have been discussed. Monsoon rainfall data of five meteorological sub-divisions, i.e., Coastal Andhra Pradesh, Rayalseema, Tamilnadu, Interior parts of South Karnataka & Kerala, for a period of 33 years (1960-92), have been utilized. The results indicate that the rainfall of Coastal Andhra Pradesh and Rayalseema has maximum impact on first principal component of southwest monsoon rainfall of five meteorological sub-divisions. The study of only first principal component is sufficient in order to understand the 49% of total variability of southwest monsoon rainfall. Analysis of first three principal components is important to understand 85% of total variability of the rainfall of this season.   On the first principal component of northeast monsoon rainfall of aforesaid five meteorological sub-divisions the impact of the rainfall of Kerala and south interior Karnataka has been found maximum. In order to understand the 56% of total variability the analysis of first principal component is sufficient.   The special negative relation is found between northeast monsoon rainfall on the Coastal Andhra Pradesh and southwest monsoon rainfall of previous year on this very sub-division and Rayalseema. The principal components of southwest monsoon rainfall may prove useful for forecasting the northeast monsoon rainfall of southern Indian plateau.  

DYNAMICS AND SPATIO-TEMPORAL VARIABILITY OF ENVIRONMENTAL FACTORS IN EASTERN AUSTRALIA USING FUNCTIONAL PRINCIPAL COMPONENT ANALYSIS

2010 ◽  
Vol 18 (04) ◽  
pp. 763-785 ◽  
Author(s):  
JUDIT K. SZABO ◽  
EUGENIO M. FEDRIANI ◽  
M. MANUELA SEGOVIA-GONZÁLEZ ◽  
LEE B. ASTHEIMER ◽  
MIKE J. HOOPER
Keyword(s):  
Principal Component Analysis ◽  
Temporal Variability ◽  
Principal Component ◽  
Component Analysis ◽  
Functional Principal Component Analysis ◽  
Geographical Information ◽  
Spatial And Temporal Variability ◽  
Functional Principal Component ◽  
Eastern Australia ◽  
Spatio Temporal

This paper introduces a new technique in ecology to analyze spatial and temporal variability in environmental variables. By using simple statistics, we explore the relations between abiotic and biotic variables that influence animal distributions. However, spatial and temporal variability in rainfall, a key variable in ecological studies, can cause difficulties to any basic model including time evolution. The study was of a landscape scale (three million square kilometers in eastern Australia), mainly over the period of 1998–2004. We simultaneously considered qualitative spatial (soil and habitat types) and quantitative temporal (rainfall) variables in a Geographical Information System environment. In addition to some techniques commonly used in ecology, we applied a new method, Functional Principal Component Analysis, which proved to be very suitable for this case, as it explained more than 97% of the total variance of the rainfall data, providing us with substitute variables that are easier to manage and are even able to explain rainfall patterns. The main variable came from a habitat classification that showed strong correlations with rainfall values and soil types.

scholarly journals Variability of southwest monsoon rainfall over West Bengal

MAUSAM ◽  
2022 ◽  
Vol 44 (4) ◽  
pp. 353-358
Author(s):  
B. BISWAS ◽  
K. GUPTA
Keyword(s):  
Seasonal Variations ◽  
West Bengal ◽  
Monsoon Rainfall ◽  
Southwest Monsoon ◽  
Seasonal Rainfall ◽  
Northern Latitudes ◽  
Rainfall Trends ◽  
Latitudinal Variations ◽  
Southwest Monsoon Rainfall

Monthly and seasonal variations of southwest monsoon rainfall over the districts of Gangetic and Sub-Himalayan West Bengal are presented and their differences discussed. Latitudinal variations of monsoon rainfall are brought out. Decadal means of seasonal rainfall over plains are compared with those at higher elevations and northern latitudes. An attempt is made to study long term rainfall trends.

scholarly journals Southwest monsoon rainfall in India: Part I-Spatial variability

MAUSAM ◽  
2021 ◽  
Vol 49 (1) ◽  
pp. 71-78
Author(s):  
A. B. MAZUMDAR
Keyword(s):  
Monsoon Rainfall ◽  
Principal Component ◽  
High Standard ◽  
Southwest Monsoon ◽  
Madden Julian Oscillation ◽  
Data Set ◽  
The Third ◽  
Rainfall Anomalies ◽  
The Mean ◽  
Southwest Monsoon Rainfall

Results of Principal Component Analysis (PCA) in spatial mode (S-Mode) applied on a 10 years' (1977-86) data set of weekly rainfall anomalies are presented in this study. The rainfall activity has been below average in the period under study with high standard deviations mostly over low rainfall areas. Inter - subdivisional correlation values suggest predominance of broad- scale weather systems over most parts of the country .The first principal component (PC) resemblance with the mean pattern. The second PC has been associated with active monsoon condition. The third and fourth PCs have been related to the northward progression of the Madden-Julian oscillation and the weak monsoon condition respectively. Resemblance of spatial patterns of alternative PCs with typical strong and weak monsoon activities suggest significant contributions from certain parts of the country (northeast, southeast) towards overall rainfall activity during weak monsoon situation.

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