報告書番号

N13004

タイトル（和文）

領域気候モデルを用いた過去53年間の気象・気候再現

タイトル（英文）

A 53-year reproduction run over Japan using a regional climate model

概要 （図表や脚注は「報告書全文」に掲載しております）

電力設備への気象外力の影響の定量的な評価を目的として，領域気候計算に対応できるように改良した領域気候モデルNuWFAS-RCMを用いて過去53年間の長期気象・気候再現計算を実施した．この領域気候モデルの計算領域は空間解像度15kmと5kmの2領域とし，初期値・境界値はECMWF再解析値を用いている．
最初に，大気中層を代表する500hPaのジオポテンシャル高度などを用いて長期連続計算の安定性を評価し，計算期間中，領域内に計算誤差が蓄積しないことを確認した．次に，過去20年間，計143地点の気象官署の観測値を用いた評価を実施した．その結果，全ての気象官署での計算値と観測値の年平均値の差は，気温0.4度，風速1.2m/s，年積算降水量81mmを示し，良好な計算精度を有することが確認できた．上記検討結果に基づき，計算結果を空間解像度5km，時間解像度1時間の高解像度・長期気象・気候データベース（CRIEPI-RCM-Era2）として整備した．

概要 （英文）

A 53-year weather and climate reproduction run was conducted over Japan region to evaluate the influence of weather and climate conditions on electric power facilities. For this purpose, we used a regional climate model (NuWFAS-RCM) based on the Advanced Research WRF (ARW), which had been improved for applying to regional climate prediction for Japan with horizontal resolutions of 15 km and 5km and with boundary conditions extracted from ECMWF reanalysis datasets for the period from Sep. 1957 to Dec. 2010.
In order to evaluate the stability of the long-term continuous run, 500hPa geopotential height and annual accumulated precipitation at the surface were examined. The result shows that numerical errors did not accumulate in the model domains during the continuous integration runs, and computational stability was confirmed. Thereafter, the performance of NuWFAS-RCM was evaluated by comparing the computational results with the surface weather observation data obtained by Japan Meteorological Agency at 143 points. First, the comparison was made for 10 sub-regions classified based on the climate characteristics during the period from Jan. 1991 to Dec. 2010. Second, the differences between the data of the model and the observation in all areas were evaluated in terms of mean temperature, mean wind and annual accumulated precipitation, and the differences of these parameters, or the biases, turned out to be 0.4 degrees Celsius, 1.2m/s and 81 mm/year, respectively. The results indicate that NuWFAS-RCM has the capability of reproducing about weather and climate with such high accuracy. Finally, the output data for the 53 years obtained by the model are compiled as a database named CRIEPI-RCM-Era2.

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