Impact of Assimilation of Radiosonde and UAV Observations from the Southern Ocean in the Polar WRF Model

• Published in: Advances in atmospheric sciences Vol. 37; no. 5; pp. 441 - 454
• Main Authors: Sun, Qizhen, Vihma, Timo, Jonassen, Marius O., Zhang, Zhanhai
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.05.2020; Springer Nature B.V; Polar Research and Forecasting Division, National Marine Environmental Forecasting Center, Beijing 100081, China%Finnish Meteorological Institute, PO Box 503, Helsinki FI00101, Finland%Geophysical Institute, University of Bergen, PO Box 7803, Bergen NO 5020, Norway; Key Laboratory for Polar Science of the State Oceanic Administration,Polar Research Institute of China, Shanghai 200136, China; College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China; The University Centre in Svalbard, PO Box 156, Longyearbyen NO 9171, Norway%College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China
• Subjects: Air temperature; Airborne observation; Antarctic Meteorology and Climate: Past; Atmospheric models; Atmospheric Sciences; Atmospheric sounding; Autonomous underwater vehicles; Data; Data assimilation; Data collection; Earth and Environmental Science; Earth Sciences; Experiments; Geophysics/Geodesy; Ice cover; Meteorology; Numerical weather forecasting; Oceans; Original Paper; Present and Future; Radiosonde data; Radiosonde soundings; Radiosondes; Sea level; Sea level pressure; Sounding; Soundings; Surface wind; Unmanned aerial vehicles; Weather forecasting; Wind; Wind speed; Southern Ocean; 资料同化; 南极; 数值天气预报; numerical weather prediction; unmanned aerial vehicles; radiosonde soundings; Southern Ocean; data assimilation; 气球探空观测; 无人机(UAV); Antarctic; 南大洋
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-020-9213-8

Weather forecasting in the Southern Ocean and Antarctica is a challenge above all due to the rarity of observations to be assimilated in numerical weather prediction (NWP) models. As observations are expensive and logistically challenging, it is important to evaluate the benefit that additional observations could bring to NWP. Atmospheric soundings applying unmanned aerial vehicles (UAVs) have a large potential to supplement conventional radiosonde sounding observations. Here, we applied UAV and radiosonde sounding observations from an RV Polarstern cruise in the ice-covered Weddell Sea in austral winter 2013 to evaluate the impact of their assimilation in the Polar version of the Weather Research and Forecasting (Polar WRF) model. Our experiments revealed small to moderate impacts of radiosonde and UAV data assimilation. In any case, the assimilation of sounding data from both radiosondes and UAVs improved the analyses of air temperature, wind speed, and humidity at the observation site for most of the time. Further, the impact on the results of 5-day-long Polar WRF experiments was often felt over distances of at least 300 km from the observation site. All experiments succeeded in capturing the main features of the evolution of near-surface variables, but the effects of data assimilation varied between different cases. Due to the limited vertical extent of the UAV observations, the impact of their assimilation was limited to the lowermost 1–2-km layer, and assimilation of radiosonde data was more beneficial for modeled sea level pressure and near-surface wind speed.