Gce Model Questions Vol1 2019 Geography Question 37

Two regions, A and B, are being assessed for their suitability for rain‑fed agriculture. The following monthly data are given (precipitation in mm, temperature in \(^\circ\)C). Solar radiation is constant at 15 MJ m\(^{-2}\) day\(^{-1}\). Region A - precipitation: 40, 45, 50, 55, 60, 70, 80, 85, 70, 55, 45, 40; temperature: 10, 12, 15, 18, 22, 25, 28, 27, 24, 20, 15, 12. Region B - precipitation: 20, 25, 30, 35, 40, 45, 50, 55, 45, 35, 25, 20; temperature: 5, 7, 10, 13, 17, 20, 23, 22, 19, 15, 10, 7. Potential evapotranspiration for a month is estimated by \(\text{PET}=0.0023\,(T+17.8)\,R_a\,30\), where \(T\) is the monthly mean temperature and \(R_a=15\). Calculate the annual aridity index \(AI = P / PET\) for each region, classify the climate using the UN desert classification (AI < 0.05 hyper‑arid, 0.05-0.20 arid, 0.20-0.50 semi‑arid, 0.50-0.65 dry sub‑humid, > 0.65 humid) and indicate which region is more suitable for rain‑fed agriculture.