Sensitivity of standardized Penman Monteith evapotranspiration estimates to climate change at Indian sub-humid locations
| dc.contributor.advisor | Tomar, A.S. | |
| dc.contributor.author | Singh, Yadvendra Pal | |
| dc.date.accessioned | 2018-07-11T05:45:31Z | |
| dc.date.available | 2018-07-11T05:45:31Z | |
| dc.date.issued | 2016-07 | |
| dc.description.abstract | The objectives of this study were, (i) to conduct sensitivity analysis of FAO56-PM model to some climatic variables; (ii) to determine sensitivity coefficient for some climatic variables and compute changes in ET0 with per unit change in them; (iii) to evaluate dominant climatic variables affecting ET0; and (iv) to evaluate trend of change in ET0 estimates on daily, monthly, and seasonal basis. The considered climatic variables were of two types, i.e. observed [maximum temperature (Tmax), minimum temperature (Tmin), maximum relative humidity (RHmax), minimum relative humidity (RHmin), sunshine duration (n), and wind speed at 2 m height (Ws)] and deduced [average temperature (Tav), average relative humidity (RHav), actual vapour pressure (ea), saturation vapour pressure (es), vapour pressure deficit (VPD), and solar radiation (Rs)]. The study was conducted for sub-humid districts of Udham Singh Nagar (Uttarakhand) and Hazaribagh (Jharkhand). The daily weather dataset of 17 years (1995-2015) and 23 years (1990-2012) collected for Udham Singh Nagar and Hazaribagh districts was used as input for calculating daily evapotranspiration (ET0) estimates using FAO56-PM model. For systematic evaluation, year was classified into 12 months (January to December) and three cropping seasons (kharif, rabi, and zaid) by grouping Standard Meteorological Weeks in tune with CWS-1 format suggested by Indian Meteorological Department, Pune, whereas, quality control of weather dataset was ensured by detecting missing data and outliers. The sensitivity analysis was conducted by increasing and decreasing value of different climatic variables from 1 to 5 units (except ea, es, VPD, and Ws). The values of ea, es, and VPD was increased and decreased with 0.4 kPa increments up to 2 kPa, whereas, Ws was increased up to 5 km d-1 only. While changing one variable at a time, no change in other climatic variables was being made to make the analysis mono-criteria. The value of daily sensitivity coefficient for each climatic variable was obtained by dividing the amount of increase or decrease in ET0 by unit change (increase or decrease) in each climatic variable to quantify change in ET0 per unit change at different timescales, whereas, dominant variable among climatic variables were decided on the basis of maximum slope. The analysis revealed that, (i) value of mean and standard deviation of daily FAO56-PM ET0 estimates for sub-humid Udham Singh Nagar and Hazaribagh districts were 3.88 mm, 3.93 mm, and 1.71 mm, 1.54 mm, respectively, (ii) response of unit change in all climatic parameters to change in daily ET0 values at both sub-humid districts was found linear with very satisfactory R² value of ≥ 0.90, except for n, Ws, and VPD for which R² varied in between 0.80 and 0.82, (iii) On the basis of slope, among observed climatic variables, change in daily ET0 was found most sensitive to Ws, followed by Tmax, and n at both districts while VPD and es were obtained as most sensitive deduced climatic variables, (iv) On monthly basis, change in ET0 estimates among observed climatic variables at both districts was found most sensitive to Ws, followed by Tmax, and n, whereas, RHmin was found most insensitive. Similarly, es was found most sensitive, followed by VPD, and Rs to change in daily ET0 estimates among deduced climatic variables, (v) On seasonal (cropping) basis, change in ET0 for rabi and zaid cropping seasons was found most sensitive to Ws, followed by Tmax, and n, while it was found least sensitive to change in RHmin among observed climatic variables, whereas, in case of deduced climatic variables, seasonal ET0 change was found most sensitive to es, followed by VPD and Rs while ea was found least sensitive at both districts. The change in ET0 in kharif in both districts was found most sensitive in decreasing order of n, Tmax, and Ws with RHmin as least sensitive, however, same trend in deduced climatic variables as observed in case of rabi and zaid i.e. es, followed by VPD and Rs was observed with ea as most insensitive and (vi) Recording of Ws, Tmax, n data and calculation of es and VPD should be made with utmost care to determine FAO56-PM estimates accurately at Indian sub-humid regions. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810058867 | |
| dc.keywords | standardization, evapotranspiration, climate change, India, humidity | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 153 | en_US |
| dc.publisher | G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand) | en_US |
| dc.research.problem | Penman Monteith Model | en_US |
| dc.sub | Agricultural Engineering | en_US |
| dc.subject | null | en_US |
| dc.theme | Irrigation | en_US |
| dc.these.type | M.Tech. | en_US |
| dc.title | Sensitivity of standardized Penman Monteith evapotranspiration estimates to climate change at Indian sub-humid locations | en_US |
| dc.type | Thesis | en_US |