Mountainous topography and solar elevation angle have a significant influence on the wind circulation and energy exchange over a complex region. Here, the seasonal variation of mountain-valley wind circulation (MVWC) and surface layer parameters have been presented over a hilly station of northeastern India. For the study, quick-response sonic anemometer data have been utilized. The solar elevation angle varies from 85° to 43° in different seasons and controls the MVWC over the terrain. MVWC was dominated in winter (WN), pre-monsoon (PM), and post-monsoon (PMN) seasons, while the synoptic wind predominates the wind direction over the terrain in monsoon (MN). In WN and PM, nighttime heat transmission from the atmosphere to the ground was −10 to −20 W m⁻², while the minimum in MN and PMN was −3 to −7 W m⁻². The net seasonal daily mean sensible heat flux (H) values from the surface to the atmosphere were 42 W m⁻², 58 W m⁻², 35 W m⁻², and 34 W m⁻² in WN, PM, MN, and PMN. In MN, the average daytime temperature was 8 °C, 0.5 °C, and 3 °C higher and at night was 9.5 °C, 2 °C, and 4.5 °C higher than the WN, PM, and PMN. In WN, PM, and PMN, the momentum flux had a higher value of about 2 to 3 h after the maximum value in H was attained at the 6-m and 10-m levels. The daytime turbulence kinetic energy was higher by 99%, 56%, 72%, and 93% than the nighttime during WN, PM, MN, and PMN.

山区地形和太阳仰角对复杂区域的风循环和能量交换有重要影响。在这里，印度东北部的丘陵站已经出现了山谷风环流（MVWC）和表层参数的季节性变化。为了进行研究，已经使用了快速响应的风速仪数据。太阳的仰角在不同季节从85°到43°不等，并控制整个地形的MVWC。MVWC在冬季（WN），季风前（PM）和季风后（PMN）季节占主导地位，而天气风主导季风（MN）上空的风向。在WN和PM中，夜间从大气到地面的热传递为-10至-20 W m ^-2，而MN和PMN中的最小值为-3至-7 W m⁻²。在WN，PM，MN，从地面到大气的净季节性平均日感热通量（H）值为42 W m ^-2，58 W m ^-2，35 W m ^-2和34 W m ^-2。和PMN。在MN中，白天的平均温度比WN，PM和PMN高8°C，0.5°C和3°C，而晚上则分别高9.5°C，2°C和4.5°C。在WN，PM和PMN中，在6m和10m处达到H的最大值后，动量通量具有较高的值，约为2至3h 。在WN，PM，MN和PMN期间，白天的湍流动能比夜间高99％，56％，72％和93％。