Wintertime mesopause temperatures observed by lidar measurements over Syowa station (69°S, 39°E), Antarctica

Abstract

A sodium lidar at Syowa station (69°S, 39°E), Antarctica, measured temperature profiles from 80 to 110 km between March and September during 2000 and 2001. Monthly averaged temperature profiles in the mesopause region in wintertime (June, July and August) are nearly 20 K lower than those in the northern hemisphere sites. The measured winter mesopause altitudes (∼99 km) are in good agreement with those measured at Fort Collins (41°N) and Andøya (69°N) in winter. The mesopause temperatures (∼175 K) in winter months however are about 20 K lower than those observed from a northern hemisphere conjugate site, Andøya. The lower winter mesopause temperatures measured at Syowa station, which are consistent with southern hemisphere mesopause temperatures measured by a shipborne lidar, suggest the existence of a hemispheric difference. Possible causes for this difference are discussed.

Mesospheric temperature estimation from meteor decay times of weak and strong meteor trails

“…Although the variations of mesopause height with the location and season are not clear yet, it has been generally known that the mesopause altitude is higher than 95 km in winter and lower than 90 km in summer (She and Lowe, 1998;Kawahara et al, 2002;Xu et al, 2007). During winter, the meteor temperatures representing the atmospheric temperature around 91 km generally exist between the rotational temperatures of OH and O 2 emissions, whose layers are known to be at the altitudes of about 87 73 km and 95 72 km, respectively (Baker and Stair, 1988;Yee et al, 1997).…”

Seasonal variations of the Na and Fe layers at the South Pole and their implications for the chemistry and general circulation of the polar mesosphere

“…Until recently, only sporadic measurements of the mesospheric metal layers at high latitudes have been reported [ Nomura et al , 1987; von Zahn et al , 1988; Gardner et al , 1988; Kurzawa and von Zahn , 1990; Alpers et al , 1990; Collins et al , 1994; Plane et al , 1998; Gardner et al , 2001; Kawahara et al , 2002; Collins and Smith , 2004]. The summer polar mesopause region is constantly illuminated by the Sun and is characterized by extremely cold temperatures and the frequent occurrence of polar mesospheric clouds (PMCs).…”

Sodium temperature lidar based on injection seeded Nd:YAG pulse lasers using a sum-frequency generation technique

“…Several intercomparison studies were done with the lidar temperature data. The mesopause temperatures (~175 K) in winter months measured at Syowa station by our lidar were about 20 K lower than those observed from a northern hemisphere conjugate site, Andøya (69°N) [9]. The lower winter mesopause temperatures suggested the existence of a hemispheric difference.…”

“…With this system, the wintertime temperature measurements in the mesopause region (80-115 km) were conducted at Syowa Station (69°S, 39°E) between May 2000 and October 2002 [9]. The red plots indicate integrated the signal of 1500 shots after subtraction of the background signal (5 counts/bin).…”

“…The prominent characteristics of the lidar transmitter include compactness to enable transportability and stable output power with low maintenance. This all-solid state, transportable lidar conducted successful observations at Syowa station in Antarctica (2000-2002) [9] and at Uji in Japan (2007OCT-2009JAN) [10] without any major trouble.…”