The purpose of this study was to understand the regional differences of crop productivity and their future prediction in Memuro Town, located in the central Tokachi region, Hokkaido. We analyzed the relationship between the yields of sugar beet roots and soil type (Brown Lowland soils, Brown Lowland soils with a volcanic ash surface, Andosols and Wet Andosols) obtained via the method of Niwa et al. (2008) and using meteorological data from AMeDAS for the surveyed area. In addition, the future differences of the root yields among soil types were predicted using the above relationship data and future climate prediction data from MIROC3.2-HIRES. The results can be summarized as follows: (1) The sugar beet root yields with respect to soil types from 1990 to 2007 were highest in Andosols. Therefore, as an index of the differences of root yield among soil types, the root yield ratio for Andosols was calculated for each soil. (2) The root yield ratios for Andosols can be explained at more than 65% for each soil by cumulative precipitation from late April to mid July. (3) According to MIROC3.2-HIRES, the average cumulative precipitation from late April to mid July for each decade (2011-2100) was predicted to be more than 200 mm. Therefore, the relationship between the root yield ratios for Andosols and the cumulative precipitation from late April to mid July were investigated for the years with more than 200 mm of cumulative precipitation during 1990-2007. As a result, a highly correlated negative secondary regression equation was obtained for each soil type. (4) Based on those regression equations and on future prediction data of precipitation, the average root yield ratios for Andosols were calculated for each decade from 2011 to 2100. When comparing the predictions to current levels until 2080, the ratios for Brown Lowland soil groups were higher, while ratios for Wet Andosols remained at the same level. However, after 2081, the average root yield ratios of both Brown Lowland soils returned to the same level as current ratios, while the ratios of Wet Andosols were predicted to be lower than the current level.
Studying the effects of greenery over residences, including roof vegetation used to reduce cooling loads, is not new. However, qualitative studies and psychological effect assessments of greenery are emphasized. Since the huge earthquake in 2011 in Tohoku, residential energy conservation has become an important goal of households: so-called green curtains have become popular. A cooling effect of some kind is expected from using green vegetation similar to blinds over windows. This study assesses the thermal cooling effect of growing bitter gourd (Momordica charantia L.) plants over windows in comparison to a cheesecloth curtain and a reed screen with and without water spraying. The outside surface temperatures of windows behind the respective screens were compared to evaluate cooling effects. The temperature behind the cheesecloth was higher, that behind a reed screen was second, and that behind the M. charantia L. was the lowest. When water spray was applied to the reed screen, the temperature behind the screen was lower than that behind the M. charantia L., which suggests that such a physical cooling system with spraying water to mimic plant transpiration is beneficial because it does not include plant care. Transpiration from the M. charantia L. was estimated using energy balance equations at both plant surfaces. Results show that this method was better than the measurement using a leaf porometer to estimate transpiration from the entire plant canopy. Because measurements using a leaf porometer take several minutes for one leaf surface, it is time consuming and not realistic to measure many leaves at a time.
We investigated historical records (e.g. old diaries, historiography, and daily newspapers) and acquired phenological data series for autumn-tinted maple (Acer spp.) leaves in Kyoto, Japan. From the 10th to 21st centuries, we gathered 504 years of phenological data for maple leaves' autumn tints. A preliminary analysis suggested that the dates of the maple autumn tints were affected by the October mean temperature. Therefore, an attempt was made to reconstruct the October mean temperature in Kyoto by applying the phenological data for autumn tints of maple leaves. Autumn temperature series partially showed a pattern similar to springtime temperature series. A cooling trend over the 15th — 16th centuries and cool conditions in the late 17th and the early 19th centuries were detected in both the October and the March temperature series; however, October temperature change preceded March temperature change by about 10—20 years. This suggests that the time-lag of response of October temperatures in Kyoto to the solar variation may be smaller than that of March temperatures.
The livelihood of people inhabiting drylands in the middle-high latitudes (such as seen in Mongolia) long has been jeopardized repeatedly by summer droughts and harsh winter conditions. Since 2000, high livestock mortality has occurred during three cold seasons in the Bulgan state, northern Mongolia. Using meteorological data from 1980 to 2012 and livestock numbers and mortality rates from 2000 to 2011, we explored features of weather conditions at the local ground level and westerlies meandering at the 500 hPa level during those high mortality cold seasons. For each cold season from October to April, we calculated the intensity of cold surges, the number and duration of days with daily temperatures below -30 °C (used as critical cold days for livestock), and the amplitude of westerlies meandering inferred from the frequency of easterly winds within a particular area, including the climatological trough of westerlies. It has been shown that the intensity of cold surges were larger (r = -0.78; P < 0.01) and critical cold days for livestock continued longer (r = 0.72; P < 0.01) when westerlies meandering were enhanced and maintained. Timely forecasting of strengthened meandering would help early warnings to mitigate or prevent livestock mortality.
Climate change will affect various sectors such as agriculture, water resources, etc. Decision-making on an emission reduction pathway of greenhouse gases (GHG) and a climate stabilization target is the issue to be solved through international cooperation. To support the decision-making of impact assessments on multiple sectors, an integrated analysis tool named AIM/Impact[Policy] was developed. In AIM/Impact[Policy], impacts of climate change on various sectors under assumed GHG-emission pathways are projected based on impact functions. An impact function is a look-up table of the country-averaged impacts on a certain sector under arbitrary conditions of climate change. In this study, we developed impact functions for maize, wheat, and paddy-rice, which will be used in AIM/Impact[Policy]. We conducted a sensitivity analysis using a full-scale impact model, named M-GAEZ model, with varying temperature and precipitation. We averaged the crop yield for each country to obtain the impact functions. According to the analysis, the sensitivity of crop yield to the temperature and the precipitation differs by both crops and countries. Among top producing countries, the maize yield in Brazil and the paddy-rice yield in Indonesia decrease in most cases. In India, the wheat yield decreases to around 30 % of the present when the temperature increases by 4 °C, that is, wheat hardly grows under such conditions. The impact functions enable us to derive the impacts on crop yield in each country under various assumptions of climate change (i.e., the changes in temperature and the changes in precipitation), and they are useful for supporting policy decisions.
In the present study, we analyzed temporal variations in both budding and leaf coloring dates of Ginkgo biloba from 1977 to 2007, as well as their degrees of similarity in the variations and geographical differences, using statistical methods. The data on the budding and leaf coloring dates were recorded by the Japan Meteorological Agency at 45 and 29 meteorological stations, respectively. Mean regression slopes between the phenological dates and the year indicated that budding in spring, on average, advanced by 1.3 days per decade, and that the leaf coloring in autumn was delayed by 3.9 days per decade. This more significant trend of the later autumn as compared with the earlier spring was supported by the results of comparisons between the mean phenological dates in the 2000s and those in the two subintervals (the 1980s and 1990s) and the comparison of temporal changes in the first principal component (PC) scores. The first PCs of the trends in the budding and the leaf coloring dates accounted for 50 % and 45 % of variations in the phenological dates, respectively. Therefore, temporal trends at approximately half of the total stations were similar. An apparent latitudinal pattern of temporal trends in the budding was indicated by the geographical distribution of the factor loadings of the second PC. The budding advanced significantly at several stations in northern Japan, which were located in cold regions. Conversely, the trends at the stations located in low latitudes and warm areas showed no clear signal. On the other hand, there was no apparent geographical pattern of temporal trends in the leaf coloring.