南極やまと山脈周辺の裸氷上における接地気層の観測

• Main Authors: 小林 俊一, Shun'ichi KOBAYASHI
• Format: Report
• Language: Japanese
• Published: 研究論文 1978
• Subjects: 551.5; Syowa Station; Yamato; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=7979; http://id.nii.ac.jp/1291/00007979/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=7979&item_no=1&attribute_id=18&file_no=1

やまと山脈周辺の裸氷原上で行った,高度約3.5mまでの接地気層の夏期間(12月)1週間の短かい観測結果から,次のことがわかった.1)風速分布から裸氷面の空気力学的粗度Z_0は,風速によらず一定で,0.085cmであった.これは裸氷表面のスプーンカットの深さ約2～3cmに対応している.2)Z_0が一定のため,摩擦速度U_*と1m高度の風速U_1との間には,U_*=0.057 U_1という直線的な関係がある.3)風が弱くなると,裸氷面の加熱のために大気は不安定になる傾向を示した.4)中立状態に近い時の渦拡散係数の値は,昭和基地周辺の雪で被われた海氷上の値よりも大きな値であった. The measurements of profiles of wind speed and air temperature in the atmospheric surface layer above bare ice surface in the circumference of the Yamato Mountains were carried out under neutral and unstable conditions in December, 1973. The results are summarized as follows: 1) The value of aerodynamic roughness parameter (Z_0) was constantly 0.085 cm independent on wind speed, and this value corresponded to the depth of spoon-cut features (2-3 cm) on the bare ice surface. 2) The relation between the friction velocity (U_*) and the wind speed at 1 m height (U_1) is expressed by U_*=0.057 U_1. 3) Atmosphere showed an unstable condition (negative Richardson number) with the decrease of wind speed, as the bare ice surface was heated by radiation. 4) Eddy diffusivity obtained on the bare ice surface in neutral condition was larger than that of sea ice around Syowa Station.