11:30 AM - 11:45 AM
[ACG43-10] Numerical simulation of intense winds near Siorapaluk in northwest Greenland
Keywords:Greenland, Lee-side downslope wind, Non-hydrostatic regional weather prediction model
In early April 2018, Niwano et al. (2018) conducted the scientific traverse expedition “Snow impurity and glacial microbe effect on the abrupt warming in the Arctic (SIGMA) Traverse 2018”. The expedition crews had initially planned to depart Siorapaluk on April 2, 2018. However, their departure was delayed by four days because of intense winds and snow blocking the way. Hashimoto et al., (2018) presented a preliminary report that the intense winds had characteristics of a lee-side downslope wind caused by air flow over the ice sheet behind Siorapaluk, based on a numerical simulation using Japan Meteorological Agency Non-Hydrostatic Model (JMA-NHM). We further studied the same windstorm in detail.
The automatic weather station (AWS) at Siorapaluk observed winds intensified up to 10 m s-1 or more from April 3 to 5. Simulated wind speed at Siorapaluk was well agree with the observation. Using the simulated wind field, we performed backward trajectory analysis. Figure 1 shows the backward trajectories from the locations above sea surface and on the coast line, and Siorapaluk, which shows that air parcels reached vicinity of Siorapaluk traveled from the northeast and beyond the ice sheet ridge line behind Siorapaluk. At the point U3 (Fig. 1) located in the upstream side of the ridge line, strongly stable layer existed below 1600 m (a.s.l.) and northwestward pressure gradient increased up to 2.5 hPa/100km intensifying northeasterly geostrophic wind during the three days. Isentropic surfaces fluttered over the lee side of ridge line showing lee-side hydraulic jump. We plan to further study how synoptic scale circulation features affect the local winds around Siorapaluk.
References
Niwano, M., T. Yamasaki and S. Yamaguchi, 2018: Arctic dog-sled expedition 2018, Seppyo, 80, 588-592. (in Japanese)
Hashimoto, A., M. Niwano, S. Yamaguchi, T. Yamasaki and T. Aoki, 2018: Numerical simulation of lee-side downslope winds near Siorapaluk in northwest Greenland. CAS/JSC WGNE Research Activities in Atmospheric and Oceanic Modelling, 48, 5.05-5.06.
Acknowledgements
This work was partly supported by the ArCSII project, and JSPS KAKENHI Grant Number JP17K12817, JP15H01733, JP16H01772, 21H03582.
The automatic weather station (AWS) at Siorapaluk observed winds intensified up to 10 m s-1 or more from April 3 to 5. Simulated wind speed at Siorapaluk was well agree with the observation. Using the simulated wind field, we performed backward trajectory analysis. Figure 1 shows the backward trajectories from the locations above sea surface and on the coast line, and Siorapaluk, which shows that air parcels reached vicinity of Siorapaluk traveled from the northeast and beyond the ice sheet ridge line behind Siorapaluk. At the point U3 (Fig. 1) located in the upstream side of the ridge line, strongly stable layer existed below 1600 m (a.s.l.) and northwestward pressure gradient increased up to 2.5 hPa/100km intensifying northeasterly geostrophic wind during the three days. Isentropic surfaces fluttered over the lee side of ridge line showing lee-side hydraulic jump. We plan to further study how synoptic scale circulation features affect the local winds around Siorapaluk.
References
Niwano, M., T. Yamasaki and S. Yamaguchi, 2018: Arctic dog-sled expedition 2018, Seppyo, 80, 588-592. (in Japanese)
Hashimoto, A., M. Niwano, S. Yamaguchi, T. Yamasaki and T. Aoki, 2018: Numerical simulation of lee-side downslope winds near Siorapaluk in northwest Greenland. CAS/JSC WGNE Research Activities in Atmospheric and Oceanic Modelling, 48, 5.05-5.06.
Acknowledgements
This work was partly supported by the ArCSII project, and JSPS KAKENHI Grant Number JP17K12817, JP15H01733, JP16H01772, 21H03582.