表面温度の年間周期の相の変化
A R Stine1, P Huybers, I Y Fung
1Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA. zan@atmos.berkeley.edu
Nature
|January 23, 2009
まとめ
地球の年間気温サイクルが早まり,振幅が変化しています. これらの気候変動は異常であり,現在の気候モデルによって完全に再現されず,さらなる研究が必要であることを示しています.
科学分野:
- 気候科学 気候科学
- 地球システム科学 地球システム科学
- 大気科学 大気科学
背景:
- 地球の表面温度の年間周期は,氷河期と氷河期間の周期に匹敵する,重要な大きさを示しています.
- 年間気温周期の段階と振幅における観測された傾向は,自然変動の理解が不十分であるため,明確な説明が欠けている.
研究 の 目的:
- 1年間の地表温度周期の相と振幅における観測された変化の原因と重要性を調査する.
- 年間気温サイクルの自然な変動性を評価し,最近の傾向と比較する.
主な方法:
- 1954年から2007年までの地表温度データの分析.
- 観測された傾向を自然変動と気候モデルのシミュレーションと比較.
- 温度サイクルシフトと北方環状モード (NAM) の関係に関する調査.
主要な成果:
- 1954年から2007年の間に,熱帯外の土地の年間地表気温サイクルが1.7日早く変化した.
- この観測された相変化は,自然の変動範囲と比較して異常である.
- 研究期間中,年間周期の振幅の有意な変化も検出されました.
- 観測されたシフトは,北の環状モードと部分的に関連していますが,相変化はNAMの予測を超えています.
結論:
- 年間気温周期の相と振幅の観測されたシフトは重要であり,自然の変動から逸脱する.
- 現在の気候モデルは,これらの観測された変化,特に季節的相変化を正確に再現することができません.
- これらの異常な気候変動の要因と影響を理解するために,さらなる研究が必要である.
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