TY - JOUR
T1 - Influences of winter climatic conditions on the relation between annual mean soil and air temperatures from central to northern Japan
AU - Yazaki, Tomotsugu
AU - Iwata, Yukiyoshi
AU - Hirota, Tomoyoshi
AU - Kominami, Yasuhiro
AU - Kawakata, Toshikazu
AU - Yoshida, Takeo
AU - Yanai, Yosuke
AU - Inoue, Satoshi
N1 - Funding Information:
We thank Dr. Shinji Suzuki at Tokyo University of Agriculture, Dr. Manabu Nemoto, Mr. Kazuhiro Shibata, Mr. Masamitsu Fujiwara, Ms. Fumi Yagasaki, and Mr. Shigeki Ishida in NARO Hokkaido Agricultural Research Center for their assistance. Constrictive comments by the anonymous reviewers improved the manuscript. This study was partially funded by the Research and Development Project for Application in Promoting New Policy for Agriculture, Forestry and Fisheries (22079) from the Japanese Ministry of Agriculture, Forestry and Fisheries.
PY - 2013/1
Y1 - 2013/1
N2 - Annual mean soil temperature (ST A) is an important factor to evaluate the potential of the productivity of agricultural fields and the amount of ground thermal resources. To assess the influence of the climate on the ST A, we collected and analyzed a field dataset at five suburban sites from central to northern Japan. Additionally, the effects of winter climate on the relation between ST A and AT A were investigated using a numerical soil temperature model. Results show that ST A was correlated positively with AT A. The difference between ST A and AT A (ST A/AT A offset) was approximately 1°C at the southern sites, where monthly mean air temperatures do not drop below 0°C. The offset, 2-4°C in the northern and colder sites, was correlated positively with the cumulative freezing degree-days (CFD). Analyses conducted using a numerical soil-temperature model revealed that the estimated ST A/AT A offset under a snow-free condition was 1.2°C on average in the northern sites, which was similar to the offset in the southern snow-free sites. This similarity suggests that the thermal insulation of snowpack was the dominant factor in raising the offset. Additionally, the numerical simulation showed that the offset reached the ceiling when the winter mean snow cover thickness (SCT mean) exceeded 0.2m under the air temperature in colder northern sites in Japan. In conclusion, although the ST A/AT A offset is known to be influenced by both CFD and SCT mean, the offset increases directly with CFD rather than SCT mean when snow cover is sufficiently thick to insulate the soil from cold air.
AB - Annual mean soil temperature (ST A) is an important factor to evaluate the potential of the productivity of agricultural fields and the amount of ground thermal resources. To assess the influence of the climate on the ST A, we collected and analyzed a field dataset at five suburban sites from central to northern Japan. Additionally, the effects of winter climate on the relation between ST A and AT A were investigated using a numerical soil temperature model. Results show that ST A was correlated positively with AT A. The difference between ST A and AT A (ST A/AT A offset) was approximately 1°C at the southern sites, where monthly mean air temperatures do not drop below 0°C. The offset, 2-4°C in the northern and colder sites, was correlated positively with the cumulative freezing degree-days (CFD). Analyses conducted using a numerical soil-temperature model revealed that the estimated ST A/AT A offset under a snow-free condition was 1.2°C on average in the northern sites, which was similar to the offset in the southern snow-free sites. This similarity suggests that the thermal insulation of snowpack was the dominant factor in raising the offset. Additionally, the numerical simulation showed that the offset reached the ceiling when the winter mean snow cover thickness (SCT mean) exceeded 0.2m under the air temperature in colder northern sites in Japan. In conclusion, although the ST A/AT A offset is known to be influenced by both CFD and SCT mean, the offset increases directly with CFD rather than SCT mean when snow cover is sufficiently thick to insulate the soil from cold air.
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U2 - 10.1016/j.coldregions.2012.09.009
DO - 10.1016/j.coldregions.2012.09.009
M3 - Article
AN - SCOPUS:84868701716
SN - 0165-232X
VL - 85
SP - 217
EP - 224
JO - Cold Regions Science and Technology
JF - Cold Regions Science and Technology
ER -