Weather radar in Nepal: opportunities and challenges in a mountainous region

Abstract

Extreme rainfall is one of the major causes of natural hazards (for example flood, landslide, and debris flow) in the central Himalayan region, Nepal. The performance of strategies to manage these risks relies on the accuracy of quantitative rainfall estimates. Rain gauges have traditionally been used to measure the amount of rainfall at a given location. The point measurement often misrepresents the basin estimates, because of limited density and high spatial variability of rainfall fields across the Himalayas. The Department of Hydrology and Meteorology (DHM), Nepal has planned to install a network of three weather radars that cover the entire country. So far, the first weather radar has been installed in 2019 in the western region of the country. Two more radars will be added for the planned radar network in the near future covering the central and eastern regions of the country. Here we introduce the first installed weather radar in Nepal. We highlight both the opportunities and challenges with the radar observation in the mountainous regions. Radar rainfall estimates across the Himalayas are critical to issue severe weather warnings; forecast floods and landslides; and inform decision making in a broad range of sectors, including water and energy, construction, transportation, and agriculture.

Appraising the Potential of Using Satellite‐Based Rainfall Estimates for Evaluating Extreme Precipitation: A Case Study of August 2014 Event Across the West Rapti River Basin, Nepal

“…Because, X-band radar has very short wavelengths (2.5-4cm), the product has a high spatiotemporal resolution (for instance, 250m and 1min). However, the observation range is limited to less than 100 km (Talchabhadel, Ghimire, Sharma, Dahal, Panthi, et al, 2021).…”

2016 Monsoon Convection and Its Place in the Large‐Scale Circulation Using Doppler Radars

“…Such agreement implies that the IMD weather radar data can successfully be used to study monsoon convection for individual years. The high temporal frequency and spatial resolution of the ground‐based radars, as well as the planting of further radars since 2016 both in India (Roy et al., 2019), and recently Nepal (Talchabhadel et al., 2021), means they are valuable resources in the analysis of storm‐scale and mesoscale phenomena for South Asia. The methodology presented here, including existing tools (e.g., Wradlib) developed using other radars (e.g., V. V. Kumar et al., 2013) should prove useful to study convection over India, especially allowing comparison across different radar sites.…”

An outlook on the applicability of satellite precipitation products for monitoring extreme precipitation events in Nepal Himalaya

“…X‐band radar provide precise precipitation information at a high spatiotemporal (approximately 250m and 1 min) resolution. However, one C‐band dual‐polarised weather radar was recently installed in the country's western region in 2019 (Talchabhadel et al ., 2022). Furthermore, the availability of high‐resolution near‐real‐time precipitation datasets helps to improve the understanding of likely hazards.…”