Intensive Urban Boundary Layer Observational Campaigns in the Arctic Cities

The Urban Heat Island (UHI) effect is well studied for moderate and low latitudes, but remains poorly studied for the Arctic. In particular, the biggest cities or Russian Arctic have been a terra incognita for the urban meteorology until recently. Our recent Urban Heat Island Arctic Research Campaign (UHIARC) as has revealed the existence of the intensive wintertime UHIs the Russian Arctic (Konstantinov et al., 2018; Varentsov et al., 2018). Such winter UHIs appear under the conditions of the calm and clear weather, typically on the background of severe frosts, and are often accompanied by air pollution events.

Our next experimental campaigns in the Artic cities were aimed to the in-depth investigation of the linkages between the winter UHIs in the Arctic cities and the boundary layer processes. This study presents the results of a new UHIARC intensive experiments, which were carried out in Nadym town in the West-Siberian Arctic (65.53N, 72.52E) in December 2018 and in Apatity town in the Kola Peninsula (67.56N, 33.4E) in January-February 2019. The intensive observational campaigns were significantly extended in comparison to the previous UHIARC studies. Canopy-layer observations included the temperature measurements with application of automatic weather stations, iButton temperature loggers and two-level Hobo temperature loggers. In order to obtain the data on thermal stratification of atmospheric boundary layer, we used the microwave temperature profiler (scanning radiometer) MTP-5 and unmanned aerial vehicles (DJI Phantom 4 Pro quadcopters), equipped by the meteorological sensors.

The intensive campaigns allowed to reveal the clear dependence between the UHI intensity and the temperature stratification of the lower atmosphere. The strongest UHIs were observed under the presence of intense surface temperature inversions. In the same time, the strong differences in the shape of temperature profile and the inversion strength were found for such conditions between the rural and urban sites. The UHI vertical extent was found to be no higher than 50 m.

Since the temperature stratification of the lower atmosphere is densely linked with a mixing ration and atmospheric pollution, the revealed dependences become especially important in terms of the air-quality and environmental issues. In addition, the collected datasets open opportunities for the verification of the high-resolution atmospheric models and urban canopy parameterizations for the stably-stratified conditions. This is especially important due to the known, but still not solved problems of reproduction of the stably-stratified conditions in the atmospheric models. This study presents the first results on the verification of the high-resolution simulations with COSMO mesoscale model with the application of the collected datasets.

Acknowledges: the study was founded by Russian Foundation for Basic Research (project no. 18-05-60126; 18-05-80065; 18-05-00715).

References:

Konstantinov et al., 2018, Environ. Res. Lett, https://doi.org/10.1088/1748-9326/aacb84

Varentsov et al., 2018. Atmos. Chem. Phys., https://doi.org/10.5194/acp-18-17573-2018