The Indian summer monsoon rainfall (ISMR) has remained remarkably stable during the last 140 years. The ISMR has varied between 70% and 120% of the long-term average of about 85 cm. Monsoon seasons with ISMR of less than 90% of the average are considered to be droughts, whereas those with more than 110% rainfall are considered as excess rainfall seasons. Although the variation is not large (Figure 1), it has a substantive impact on our agriculture and gross domestic product (GDP).
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/monsoon-prediction-are-dynamical-models-getting-better-statistical-models
[2] http://admin.indiaenvironmentportal.org.in/category/author/sulochana-gadgil
[3] http://admin.indiaenvironmentportal.org.in/category/author/j-srinivasan-0
[4] http://admin.indiaenvironmentportal.org.in/category/journal/current-science
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/monsoons
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/weather-predictions
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bay-bengal
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/indian-meteorological-department-imd
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/atmosphere