Somnath Baidya Roy

Impacts of wind farms on surface air temperatures

Utility-scale large wind farms are rapidly growing in size and numbers all over the world. Data from a meteorological field campaign show that such wind farms can significantly affect near-surface air temperatures. These effects result from enhanced vertical mixing due to turbulence generated by wind turbine rotors. The impacts of wind farms on local weather can be minimized by changing rotor design or by siting wind farms in regions with high natural turbulence. Using a 25-y-long climate dataset, we identified such regions in the world. Many of these regions, such as the Midwest and Great Plains in the United States, are also rich in wind resources, making them ideal candidates for low-impact wind farms.

A Short-Term Ensemble Wind Speed Forecasting System for Wind Power Applications

AbstractThis study develops an adaptive, blended forecasting system to provide accurate wind speed forecasts 1 h ahead of time for wind power applications. The system consists of an ensemble of 21 forecasts with different configurations of the Weather Research and Forecasting Single Column Model and persistence, autoregressive, and autoregressive moving-average models. The ensemble is calibrated against observations for a 6-month period (January–June 2006) at a potential wind-farm site in Illinois using the Bayesian model averaging technique. The forecasting system is evaluated against observations for the July 2006–December 2007 period at the same site. The calibrated ensemble forecasts significantly outperform the forecasts from the uncalibrated ensemble as well the time series models under all environmental stability conditions. This forecasting system is computationally more efficient than traditional numerical weather prediction models and can generate a calibrated forecast, including model runs and ...

Mesoscale moisture transport effects on forest edges in a fragmented landscape in Amazonia

This work explores the dry season micrometeorology of fragmented forests in Amazonia. Numerical simulations with a coupled atmosphere-vegetation model show that mesoscale moisture transport leads to a significant drying and vegetation stress at the forest edges. Increased evaporation cannot fully compensate for the drying. Typical convective precipitation events that occur in the dry season have a localized impact and do not affect the drying trend in the long term. Availability of soil moisture can partially mitigate the drying effect and consequent vegetation stress. Edge effects can dominate the vegetation dynamics and fire susceptibility of forest fragments as a whole. Hence, understanding the dynamics and drivers of edge effects is crucial for understanding the ecology and future of tropical forests in a changing climate.