Trend analyses of regional time series of temperatures and rainfall of the Tapi basin

Climate change information at the scale of basin is vital for planning, development and use of water. The Tapi basin is climatically responsive. Hydrological response of a basin is based mainly on rainfall and temperature. Variations in climate at regional scales impacts fundamental features of our life. Thus, in the present work, trend analyses of regional time series (1971-2004) of minimum, mean, maximum temperatures and rainfallis performed for monthly, annual and seasonal scales for the Tapi basin. Correlogram is utilized for evaluation of dependence of data. Mann-Kendall test and Mann-Kendall test with block bootstrapping are applied for the evaluation of trend significance. Sen’s slope test is applied for the evaluation of trend magnitude. Sequential Mann-Kendall test is applied for assessment of beginning and end of the trend. Statistically significant positive trends are detected in regional annual and winter Tmean time series with their beginning in years 1974 and 1972, respectively.

Prehistoric landscapes, humans and ostriches: Highlighting geoarchaeological issues in the Tapi basin of Maharashtra (west-central India) - A multidisciplinary approach

The formal beginning of geoarchaeology in India can be traced back to 1863 when the first Palaeolith was documented and collected by Robert Bruce Foote in Tamil Nadu and later described in a detailed geological context. Today, various geological tools such as geospatial analytical tools are available to provide extra mileage to geoarchaeological investigations. They supplement field evidence and enable researchers to display, manipulate, and model geological data and the associated archaeological evidence. The present paper attempts to summarise the current status of understanding the Quaternary geoarchaeology of the Tapi River basin in west-central India. The aspects considered include geomorphology, landform evolution, morphometric parameters, relationships between climate and basin evolution, and Palaeolithic and Mesolithic evidence. This present study uses Landsat imagery, locational data, Survey of India (SOI) topographic sheets and Shuttle Radar Topography Mission (SRTM) data in ArcGIS software. The study is the first comprehensive attempt to summarise the issue of prehistoric human adaptations (dominated mainly by Late Pleistocene evidence) through changing environments, with an assumption that the two occurred in synchronisation. Another assumption is that the reported lithic and fossil sites and the surrounding areas have preserved signatures of original landforms and sedimentary contexts.Through these perspectives and visual integration of topography, drainage networks and Landsat image parameters in a Geographic Information System (GIS) platform, along with other variable field inputs, a testable hypothetical model of the Quaternary evolution of Central Tapi valley is proposed. Additionally, an AMS date of 47,145 cal BP for a newly-discovered ostrich eggshell fragment from Sakegaon near Bhusawal is presented and its palaeoanthropological implications are discussed. Altogether, our observations from the study area, such as an expansion of land use from the Acheulean onwards, signatures of arid phases and the oldest reported ostrich eggshell (OES), warrant further detailed multidisciplinary research. An in-depth understanding of the first-to-last occurrences of ostriches in the region and comprehensive picture of their pan- South Asian distribution, in general, will help address the issue of prehistoric human adaptations through changing environments.