Winter 2018 major sudden stratospheric warming impact on midlatitude mesosphere from microwave radiometer measurements

Abstract

The impact of a major sudden stratospheric warming (SSW) in the Arctic in February 2018 on the midlatitude mesosphere is investigated by performing the microwave radiometer measurements of carbon monoxide (CO) and zonal wind above Kharkiv, Ukraine (50.0 • N, 36.3 • E). The mesospheric peculiarities of this SSW event were observed using a recently designed and installed microwave radiometer in eastern Europe for the first time. Data from the ERA-Interim and MERRA-2 reanalyses, as well as the Aura microwave limb sounder measurements, are also used. Microwave observations of the daily CO profiles in January-March 2018 allowed for the retrieval of mesospheric zonal wind at 70-85 km (below the winter mesopause) over the Kharkiv site. Reversal of the mesospheric westerly from about 10 m s −1 to an easterly wind of about −10 m s −1 around 10 February was observed. The local microwave observations at our Northern Hemisphere (NH) midlatitude site combined with reanalysis data show wide-ranging daily variability in CO, zonal wind, and temperature in the mesosphere and stratosphere during the SSW of 2018. The observed local CO variability can be explained mainly by horizontal air mass redistribution due to planetary wave activity. Replacement of the CO-rich polar vortex air by CO-poor air of the surrounding area led to a significant mesospheric CO decrease over the station during the SSW and fragmentation of the vortex over the station at the SSW start caused enhanced stratospheric CO at about 30 km. The results of microwave measurements of CO and zonal wind in the midlatitude mesosphere at 70-85 km altitudes, which still are not adequately covered by ground-based observations, are useful for improving our understanding of the SSW impacts in this region.

Small-scale variability of stratospheric ozone during the sudden stratospheric warming 2018/2019 observed at Ny-Ålesund, Svalbard

“…In Bern water vapour increased by 15 % (Flury et al, 2009), whereas at Seoul a water vapour decrease of 40 % was observed (De Wachter et al, 2011). The zonal wind reversals could be observed during several SSWs at midlatitudes and in the Arctic (Wang et al, 2019;Rüfenacht et al, 2014;Schranz et al, 2019).…”

“…For the period when primarily EOS-MLS data were assimilated in the reanalysis (2003-2012), a comparison with MIPAS measurements was performed. It shows that MERRA-2 underestimates ozone VMRs by up to 5 % compared to MIPAS during winter (DJF) in the Arctic stratosphere (100-1 hPa) (Wargan et al, 2017).…”

Antarctic Ozone Enhancement During the 2019 Sudden Stratospheric Warming Event

“…The vortex initially forms because of the large meridional temperature gradient near the polar terminator during winter (Solomon, 1999). Since the northern polar vortex is generally more disturbed by planetary waves generated by the variable surface topography existing in the Northern Hemisphere (NH), SSW occur frequently in the NH every second year on average (e.g., Blume et al, 2012; Charlton & Polvani, 2007; Wang et al, 2019, among others). Examples of documented SSW events in the Southern Hemisphere (SH) are the 2002 event (Krüger et al, 2005; Varotsos, 2003; WMO, 2002) and the 2010 SSW event (de Laat & van Weele, 2011; Eswaraiah et al, 2018).…”

Planetary Wave Spectrum in the Stratosphere–Mesosphere during Sudden Stratospheric Warming 2018

“…The vertical structure of the polar vortex determines the propagation of the planetary waves (Rossby waves) that penetrate into the middle atmosphere from the troposphere [4][5][6][7][8]. At high activity of planetary waves, the polar vortex is weakening or even change the zonal wind direction from westerly to easterly, when sudden stratospheric warming (SSW) event is observed [9][10][11][12][13][14] and the destruction of the vortex is accompanied by a sharp increasing of the polar stratosphere-mesosphere temperature [1,[15][16][17].…”

“…The main goal of this paper is to investigate a planetary wave spectrum in the SSW 2018. We study the planetary wave manifestations in the stratosphere and the mesosphere over the Kharkiv region in order to continue analysis of the mesospheric carbon monoxide from the microwave radiometer measurements in Kharkiv [12]. In Section 2, the data and methods of spectral and wavelet analysis of the data are described.…”