Temperature Trends at the National Agricultural Research Center for Hokkaido Region in the 40 Years from 1966 to 2005

Sameshima, Ryoji; Hirota, Tomoyoshi; Hamasaki, Toshimitsu; Suzuki, Shinji

doi:10.2480/agrmet.63.95

Cited by 9 publications

(5 citation statements)

References 5 publications

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“…The observed long-term trends in the DJF mean of min are +4.84 °C 100 yr À1 at Sapporo and +0.93 °C 100 yr À1 at Suttu, while the JJA mean of T max is +0.82 °C 100 yr À1 at Sapporo and +0.74 °C 100 yr À1 at Suttu (Table 1), indicating a higher warming rate in Sapporo than in Suttu, especially in winter T min . Observation at Suttu has also been influenced by local-scale environmental change [Sameshima et al, 2007], which is important for long-term temperature trends as described in Pielke et al, 2007b andFall et al [2011]. In addition, in September 1989, the observatory at Suttu was redeployed to the current location, approximately 1500 m west-northwest from the coastal area where the previous site was located.…”

Section: Model and Numerical Setupmentioning

confidence: 99%

Seasonal and diurnal variability in historical warming due to the urbanization of Hokkaido, Japan

2015

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The influence of historical urbanization on warming trends observed on Hokkaido Island (Japan) is discussed with an emphasis on seasonally and diurnally differential responses of air temperature to urban effects. Two numerical experiments using past and current land use scenarios successfully simulated the observed temperature trends, showing a greater rate of warming in winter than in summer and a greater increase in daily minimum than daily maximum temperatures. The results suggest that seasonal and diurnal variations in the thermal structure of the planetary boundary layer play a leading role in determining the warming rate of surface air. Under strongly stable stratification, anomalous heating within the urban canopy dissipates into a near-surface shallow layer, resulting in increased daily minimum temperatures during winter. In summer, however, anomalous urban heating due to increased Bowen ratios is attenuated by vertical mixing in the convective daytime boundary layer, suppressing the impact of urban heating on surface warming.

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Section: Model and Numerical Setupmentioning

confidence: 99%

Seasonal and diurnal variability in historical warming due to the urbanization of Hokkaido, Japan

2015

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“…The meteorological record at NARCH, which goes back more than 40 years, was regarded as representative of the surrounding agricultural area (Sameshima et al, 2007); the air temperature there was 1-2 lower than that at the JMA station located in central Sapporo, approximately 10 km distant from NARCH. We treated the air temperature data at NARCH and NARCT as that at Sapporo and Morioka, respectively.…”

Section: Meteorological Datamentioning

confidence: 99%

Assessment of paddy rice heading date under projected climate change conditions for Hokkaido region based on the field experiment

Nemoto

Hamasaki

Sameshima

et al. 2011

J. Agric. Meteorol.

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Impact assessment and adaptation planning to enable growth of paddy rice (Oryza sativa L.) under conditions of ongoing climate change are necessary in the Hokkaido region of northern Japan because of the intensive climate warming ( 2-3 in summer) projected to occur during the 21st century. Most previous studies have been based on extrapolation of results from past and present experimental data on unexperienced warming conditions under projected climatic change. These facts motivated us to use an assessment method known as an open-field day-length-extension (ODE) experiment. First, we confirmed the feasibility of an ODE experiment, which involves artificially extending day length with supplemental lighting. ODE treatment was performed in Morioka in 2009 (treatment ODE09M), where the summer temperature was 2.5 higher than the current average summer temperature in Sapporo, and the results were compared with those obtained in Sapporo, Hokkaido, in 2010 (treatment C10S), which had an extraordinarily hot summer (mean daily temperature 2.3 higher than normal). The difference in heading date between ODE09M and C10S was small, i.e., 4 days for the three cultivars Koshihikari, Hitomebore, and Akitakomachi. Second, by comparing previous temperature gradient chamber (TGC) results with those from the ODE experiment, we found that a TGC experiment system was likely to overestimate the effect of temperature on heading date by up to 7 days. Finally, we calculated paddy rice cultivation under projected climate change conditions in Sapporo in terms of three critical dates for stable rice cultivation: the early limit for transplanting, the early limit for heading, and the late limit for heading. The warmer climate condition at Morioka formed by the ODE experiment that is an analog of future climate (2.5 higher than the current average) at an northern site, Sapporo, would allow successful cultivation of Hitomebore and Akitakomachi, but not Koshihikari, in Sapporo.

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“…The air temperatures were measured using a PT-100 sensor HMP155; Vaisala Corp., Helsinki, Finland in a ventilation tube at a height of 1.9 m at 1 min time intervals as described by Yazaki et al 2017 or using portable thermometers TR-52i, T&D Corporation, Tokyo, Japan in a natural ventilated shelter at a height of 1.8 m at 1 h time intervals N = 6 and 14, respectively . We preliminarily compared daily mean air temperatures obtained by natural and forced ventilation systems at four sites for 2 years and confirmed that the root-mean-square error RMSE caused by the use of a natural ventilation system was ~0.36 C. Sameshima et al 2007 also reported that the RMSE in daily minimum air temperature was small 0.3 C . We conducted quality control on the basis of the daily mean, minimum, and maximum air temperatures, and removed anomalies ~6 of total records .…”

Section: Study Domain and Meteorological Observationmentioning

confidence: 54%

“…Note also that the earlier validations were conducted using AMeDAS data, which were usually of urban area, whereas most of the present sites were located near farmland. Sameshima et al 2007 compared 40 year temperature records obtained at several AMeDAS stations and at a meteorological station surrounded by farmland and reported a greater urbanization effect at AMeDAS stations. This could lead to greater positive deviations at AMeDAS stations and hence cause overestimations of T int at interpolated sites near farmland.…”

Section: Variability Of the Bias In The Interpolated Daily Mean Air Tmentioning

confidence: 99%

Bias correction for spatially interpolated daily mean air temperature during winter in eastern Hokkaido using multimodal machine learning

Murakami

Hirota

Shimoda

et al. 2020

J. Agric. Meteorol.

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Interactions between boundary layer wind and topography form non-uniform air temperature distributions in cold and snow-covered regions. Because of this heterogeneity, spatially interpolated air temperatures sometimes deviate from observed values. To evaluate the quality of spatially interpolated daily mean temperatures T int provided by a 1 km gridded meteorological data service Ohno et al., 2016 , we collected observed temperatures T obs obtained at meteorological observation sites located near farmland in the Tokachi and Okhotsk regions in eastern Hokkaido, Japan in winter October-March and revisited the bias in the interpolated temperatures dT. The root-mean-square error RMSE of T int obtained at 88 sites was 1.16 C, and the absolute median dT values were greater than 1 C at 14 sites. The variance of dT was greater on cold and calm days, suggesting the involvement of radiative cooling and the accumulation of cold air parcels. To correct T int by estimating dT at a given site by considering the formation mechanisms of the temperature distributions, we attempted to develop a multimodal machine learning model that had four predictors: surface and boundary layer meteorological data and topographical and geographical features around each site. To analyze the influence of the spatial extent of the topography and geography around each site, we compared models having these predictors with various sizes of the region of interest ROI. By training the models and applying them to an independent test dataset, it has been shown that bias correction using models with a small topographical ROI 30 30 km or smaller reduced the RMSE. The RMSE of the test dataset decreased by ~0.1 C via the application of a nested model, suggesting the potential usefulness of the presented approach for locally confined meteorological events. However, the biases were increased at several sites by application of the models, thus implying that further improvement is essential for practical use.

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Temperature Trends at the National Agricultural Research Center for Hokkaido Region in the 40 Years from 1966 to 2005

Cited by 9 publications

References 5 publications

Seasonal and diurnal variability in historical warming due to the urbanization of Hokkaido, Japan

Seasonal and diurnal variability in historical warming due to the urbanization of Hokkaido, Japan

Assessment of paddy rice heading date under projected climate change conditions for Hokkaido region based on the field experiment

Bias correction for spatially interpolated daily mean air temperature during winter in eastern Hokkaido using multimodal machine learning

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