Intercomparison of evapotranspiration estimates     

S. MOHAN 《水文科学杂志》2013,58(5):447-460

Abstract

Five methods of computing reference evapotranspiration from a reference crop (Penman, radiation, Blaney-Criddle, Hargreaves and pan evaporation) have been studied for their applicability under different climatic conditions. The Penman method was taken as the standard and the other four methods were compared against this method. Good correlation was obtained between the values estimated by the four methods and the Penman method although differences in magnitude were found. Regression equations were developed to correct those differences in magnitude. The method suitable for the estimation of reference evapotranspiration for each climatic condition is also suggested.  相似文献   

Author Index 1991     

S. MOHAN  N. ARUMUGAM 《水文科学杂志》2013,58(6):689-691

Abstract

Evapotranspiration (ET) is an important process in the hydrological cycle and needs to be accurately quantified for proper irrigation scheduling and optimal water resources systems operation. The time variant characteristics of ET necessitate the need for forecasting ET. In this paper, two techniques, namely a seasonal ARIMA model and Winter's exponential smoothing model, have been investigated for their applicability for forecasting weekly reference crop ET. A seasonal ARIMA model with one autoregressive and one moving average process and with a seasonality of 52 weeks was found to be an appropriate stochastic model. The ARIMA and Winter's models were compared with a simple ET model to assess their performance in forecasting. The forecast errors produced by these models were very small and the models would be promisingly of great use in real-time irrigation management.  相似文献   

Fossil Steginoporellid (Cheilostomata: Neocheilostomina), Bryozoa from the Tertiary sediments of Western Kachchh, Gujarat, India     

MOHAN A SONAR  SHARAD G GAIKWAD 《Journal of Earth System Science》2013,122(1):149-161

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Geomorphological study of sundarban deltaic estuary     

Dipnarayan Ganguly  Anirban Mukhopadhyay  Rahul Krishna Pandey  Debasish Mitra 《Journal of the Indian Society of Remote Sensing》2006,34(4):431-435

Study of landforms in Sundarbans deltaic estuary is necessary in regular basis due to its importance and impact on ecology, climate and economy. Remote sensing has proved as an important tool to study this. Multi-temporal satellite data helps to delineate the various geomorphic classes in different time domain and also provide inputs to study the coastal erosion and accretion. Finer spatial and better temporal resolution will be an added adventure for this kind of study.  相似文献   

COMMENT ON “A NOTE ON THE USE OF A NOMOGRAM FOR SELF-POTENTIAL ANOMALIES” B.B. BHATTACHARYA AND N. ROY*     

N.S. RAJAN  N.L. MOHAN  M. NARASIMHA CHARY 《Geophysical Prospecting》1986,34(8):1292-1293

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Seismic Hazard Assessment of Dhanbad City,India, by deterministic approach     

Sinha  Rahul  Sarkar  Rajib 《Natural Hazards》2020,103(2):1857-1880

Natural Hazards - Dhanbad is the largest producer of coal in the state of Jharkhand, India, and hence, it is one of the most important cities in the country. Considering the present-day importance...  相似文献   

Dramatic decline of Arctic sea ice linked to global warming     

Yadav  Juhi  Kumar  Avinash  Mohan  Rahul 《Natural Hazards》2020,103(2):2617-2621

Natural Hazards - Arctic sea ice has declined rapidly over the past four decades at the rate of ??4.7% per decade leading to an imbalance in the oceanic heat flux. The study reported...  相似文献   

Benthic Disturbance and Impact Experiments in the Central Indian Ocean Basin     

Rahul Sharma  B. Nagendernath  A. B. Valsangkar  G. Parthiban  K. M. Sivakolundu  Gavin Walker 《Marine Georesources & Geotechnology》2000,18(3):209-221

As a part of the Environmental Impact Assessment studies for nodule mining, a long-term program has been initiated in the Central Indian Basin. Multidisciplinary studies on geological, biological, physical, and chemical parameters were carried out in an area selected on the basis of baseline data collected in the first phase of the program. A benthic disturbance was simulated with a hydraulic device also used in the previous experiments in the Pacific Ocean. A site of 3,000 ×200 m was repeatedly disturbed by a combination of fluidizing pump and suction pump to dislodge and discharge sediment from the seafloor into the water column 5 m above the seafloor. During 9 days of operation, 26 tows were carried out for 47 h of disturbance, resuspending about 6,000 m 3 of sediment along an 88-km line. Data for postdisturbance impact assessment were collected with sediment traps, deep-towed cameras, seafloor samples, and conductivity-temperature depth sensor (CTD)-rosette observations. Seafloor data, sediment samples, and water column studies were aimed at evaluating the impact of benthic disturbance, on the basis of pre- and postdisturbance data collected during the experiment. Observations show that vertical mixing of sediment as well as its lateral movement and resedimentation because of plume migration alters various parameters and leads to changes in the environment around the area.  相似文献   

Siltation in Nizamsagar reservoir: environmental management issues     

Rahul Chettri  B. Bowonder 《Applied geography (Sevenoaks, England)》1983,3(3):193-204

The Nizamsagar is one of the most heavily silted Indian reservoirs, with a 60 per cent reduction in its storage capacity in just 40 years. At the present rate of siltation, the entire original storage capacity will have silted up in 70 years. The problem of siltation has a multitude of economic and environmental implications. The environmental management issues involved in the siltation of the Nizamsagar are identified and analysed in detail in this paper. Regular monitoring of siltation and the taking of timely corrective action would have reduced the extent of damage by siltation.  相似文献   

Evaluation of the Holocene environmental changes of the southwest coast, India: A palaeopalynological approach     

B AJAYKUMAR  K SREEDHARAN  MAHESH MOHAN  JOBY PAUL  A P THOMAS  P K K NAIR 《Journal of Earth System Science》2012,121(4):1093-1103

The climatic variability and the influence of temperature and sea level fluctuations on the earth??s surface configuration during the Holocene are being discussed all over the world. The present study evaluates the palaeo-environmental conditions of western coast of India during this epoch through the analysis of pollen grains embedded in a carbonaceous clay formation (? 0.4?C0.6?m) found sandwiched within the palaeodeposit of sand of Meenachil River basin. The carbon dating revealed that the clay formation has an age of 5786 ± 94 ¹⁴C yr BP, while the embedded wood samples have the age varying in between 2888 ± 78 and 5780 ± 95 ¹⁴C yr BP. The overall analysis suggests that the southwestern margin of India had experienced high intensity rainfall during the earlier part of the Atlantic chronozone due to then strengthened Asiatic monsoon, while water stagnation and hydrological modifications were observed during the later part. The dominance of weeds and lesser number of tree elements suggested a drier climate during the end of the Atlantic period. Besides, the morphometric rearrangement of the Meenachil River contemporaneous to the geomorphological modifications of the southwestern coast of India shall be classified into three categories: (1) Pre-Vembanad Lake formation, (2) Contemporaneous to lake formation and (3) Post-Lake formation.  相似文献