Average Annual Minimum Temperature Research Articles

Interdecadal variation of potato climate suitability in China

A scientific description of climate suitability of crop distribution is of great significance to mitigate negative effects of climate change and ensure food security. We investigated for the first time the potential impact of climate change on potato distribution at a national scale. The interdecadal change of potato distribution in China in response to the climate change from 1961 to 2017 was estimated using the MaxEnt model. The annual precipitation, annual average minimum temperature, average temperature in the coldest month, and sunshine duration were selected to model the climate suitability of potato distribution. The climate optimum areas exhibited a shrinking trend, with proportion of acreage falling from 5.12 % in the 1960s to 3.49 % in the 2010s. Climate suitable areas showed the tendency to expand to the east and shrink to the north. As an illustration, the climate suitability in eastern part of North-central Region was increased, but was decreased in southern part of Southwest Region. The proportions of consistency between major planting areas and high climate suitability areas were decreased from 93.36 % in the 1980s to 79.62 % in the 2010s. The increase of potato acreage in low climate suitable areas such as Middle and Lower Reaches of Yangtze River Region, Southeast Region, and southern part of Southwest Region might bring an adverse effect to potato production. Given that the climate optimum areas were found in the marginal regions of mid-western Xinjiang province in the past 60 years, it might be potential areas for potato introduction. The evaluation of climate suitability could provide a theoretical reference for planting layout of potato, which was conducive to reducing the potential risk of climate change on potato production and developing a reasonable regionalization of climate suitability.

Spatiotemporal variability of air temperatures in Central Serbia from 1949 to 2018

The paper presents trends for three categories of variables: average annual, average maximum and average minimum air temperatures. Data was provided by the meteorological yearbooks of the Republic Hydrometeorological Service of Serbia. The main goal of this paper is to detect possible temperature trends in Central Serbia. The trend equation, trend magnitude, and Mann-Kendall non-parametric test were used in the analysis of climate parameters. The used statistical methods were supplemented by GIS numerical analysis, which aimed to analyze the spatial distribution of isotherms from 1949 to 2018. The obtained results indicate that out of the 72 analyzed time series, an increase in air temperature is dominant in 61 time series, while 11 time series show no changes. The highest increase was recorded in the average maximum time series (4.2 °C), followed by an increase of 3.5°C in average maximum air temperatures. The highest increase in the average annual time-series was 3.0 °C. The lowest increases in air temperature were recorded in the average minimum time series (0.1 and 0.2 °C). In two average minimum time series a decrease in average air temperatures was identified (-0.6 and -0.4 °C. The application of GIS tools indicates the existence of interregional differences in the arrangement of isotherms, leaded by the orography of the terrain. In the spatial distribution of the analyzed variables, "poles of heat" and "poles of cold" stand out, and the influence of the urban heat island is evident (especially in the case of the urban agglomeration of Belgrade). The manifested spatial patterns of air temperature need to be further examined and the correlation with possible causes need to be determined. For these reasons, the paper provides a solid basis for studying the climate of this area in the future, as it provides insight into climate dynamics over the past decades.

Temperature reconstruction based on 361 year old dendrochronology of Platycladus orientalis (L.) franco in the Wula Mountains, China

The northern edge of the East Asian monsoon region is also a transition zone of temperate continental and monsoon climate, which is a sensitive zone of global climate and ecological environment change. It is an urgent problem to find out the long-term climate change rules of this region. Using 101 tree core samples obtained from 54 trees, a 343-year tree-ring width chronology of the Platycladus orientalis (L.) Franco (1673–2016) in the Wula Mountains, Inner Mongolia, China was established. The analysis shows that the radial growth of P. orientalis is closely related to hydrothermal conditions, the average minimum temperature and relative humidity are the main factors that determine the growth of P. orientalis. Based on the strong correlation between the tree-ring indices and the annual average minimum temperature (r = −0.870, p < 0.001), we reconstructed an average annual minimum temperature series from 1673 to 2016 using a linear regression equation, and the reconstructed equation can explain 75.724% of the variance, respectively. According to the data from the past 343 years, the changes in the annual average minimum temperature series had the cycles of 58.6-, 7.7-, 3.4-, 3.1-, 2.2-, and 2.1-years; the series showed three warm periods (1824–1830, 1909–1922, and 1986–2011) and 4 cold periods (1703–1712, 1731–1738, 1754–1763, and 1937–1951). The low temperature periods recorded in the reconstructed series for the 17th and 18th centuries are consistent with the Little Ice Age that occurred in the northern hemisphere, and the heating rate significantly increased at the end of the 20th century. In addition, the cold and warm periods recorded by the reconstruction result is basically consistent with the extreme climate events recorded in the historical documents of the region and the reconstruction results in other regions. In this paper, the world's first chronology of P. orientalis tree ring width was established. A historical sequence of annual average minimum temperature of 343 years was reconstructed in a typical region of the East Asian monsoon climate. It fills in the blank of reconstruction sequence and variation characteristics of mean minimum temperature in the northern edge of East Asian monsoon and transition zone of temperate continental and monsoon climate in recent four centuries.

Long-Term Trend Analysis in Annual and Seasonal Precipitation, Maximum and Minimum Temperatures in the Southwest United States

The objective of this study is to perform trend analysis in the historic data sets of annual and crop season [May–September] precipitation and daily maximum and minimum temperatures across the southwest United States. Eighteen ground-based weather stations were considered across the southwest United States for a total period from 1902 to 2017. The non-parametric Mann–Kendall test method was used for the significance of the trend analysis and the Sen’s slope estimator was used to derive the long-term average rates of change in the parameters. The results showed a decreasing trend in annual precipitation at 44.4% of the stations with the Sen’s slopes varying from −1.35 to −0.02 mm/year while the other stations showed an increasing trend. Crop season total precipitation showed non-significant variation at most of the stations except two stations in Arizona. Seventy-five percent of the stations showed increasing trend in annual maximum temperature at the rates that varied from 0.6 to 3.1 °C per century. Air cooling varied from 0.2 to 1.0 °C per century with dominant warming phenomenon at the regional scale of the southwest United States. Average annual minimum temperature had increased at 69% of the stations at the rates that varied from 0.1 to 8 °C over the last century, while the annual temperature amplitude showed a decreasing trend at 63% of stations. Crop season maximum temperature had significant increasing trend at 68.8% of the stations at the rates varying from 0.7 to 3.5 °C per century, while the season minimum temperature had increased at 75% of the stations.

The characteristics of climate changes over Nantong during the period 1951-2018

Climate change is a hot issue concerned by governments, society and scientists all over the world. Some measures will be developed by the governments after studying district climate change. Based on climate dates such as average temperature, average maximum temperature, average minimum temperature, and precipitation at the monthly scale obtained from eight meteorological stations over the Nantong region in Jiangsu province during the Period 1951-2018 in this paper. Climate change law was studied. This research methods include accumulative anomaly method, linear trend estimation, Mann-Kendall trend test and Morlet wavelet analysis. Results showed as following: (1) temperature has an obviously upward trend, but the differences between annual average temperature, annual average maximum temperature, and annual average minimum temperature are at little level. The trend in precipitation is not prominent in the period. The average values for the first 10 years of this century and the last 30 years are the chronological and period maximum. (2) The increase rate of temperature in spring is greatest during four seasons, and the significant is also the biggest. The increase rate of temperature in winter is greater than autumn, but the significant is reverse. Precipitation increases in summer and winter, but decrease in spring. (3) Mutation years of temperature and precipitation change were mainly in 1996-1998 and 2002-2004. (4) For period change, temperature and precipitation showed stable changes at a shorter time scale, such as 10 years or 2-3 years, and some longer scale period change for 30 years for mean average temperature. Overall, climate change over Nantong was consistent with other regions in China, and it also had its own unique features in some aspects.

Impacts of cyclone and flood on crop and fish production in disaster prone coastal Bhola district of Bangladesh

This study assessed the impact of climate change induced disaster on crops and fisheries production at Bhola Sadar and Monpura upazila of Bhola district, Bangladesh during January to June 2018. The study was gathered primary data from primary observation (PO), questionnaire survey (QS), focus group discussion (FGD), and key informant interview (KII). Secondary data were collected from Upazila Agricultural Office and Upazila Fisheries Office of Bhola Sadar and Manpura upazila and moreover, climatic data were collected from Bangladesh Meteorological Department. Results of the study found that trend analysis indicates overall annual maximum temperature increased for Kharif-I, Kharif-II and Rabi season. Average annual minimum temperature also increased for Kharif-I season but decreased for Kharif-II and Rabi season. Study also found that for all cropping season average relative humidity was increased. Annual average rainfall exhibited decreasing trend for Kharif-I and Rabi season but increased for Kharif-II season in (1990-2019) time period. The Aus, T. Aman, Boro and Mung bean was dominant cropping pattern in Kharif-I, Kharif- II and Rabi season in Bhola district. Overall, Aus rice production in Kharif-I season increased but in 2009, 2013 production was decreased because of cyclone Aila (2009) and Cyclone Mahasen (2013). T. Aman production hampered due to Cyclone Sidr (2007) and flood (2014) in Kharif-II season. In Rabi season Boro rice production lessen because of low rainfall and salinity intrusion. Overall, Mung bean production increase but in 2008 and 2009 production become hampered due to late cultivation because of Cyclone Sidr (2007). Fish production rate increase in Bhola specially Hilsha fish because of non-climatic factor like raid in non-fishing time, banned current net but fish production in pond become diminished due to infrequent natural disaster. Practicing of salt and flood tolerant varieties, floating bed vegetable cultivation, and mixed cropping system (mainly for Rabi season), enhanced expedition activities against catching mother Ilish in prohibition period, dredging in the heart of the river which can eventually reduce vulnerabilities and increase crop and fish production in the Bhola region.&#x0D; Int. J. Agril. Res. Innov. Tech. 10(1): 40-55, June 2020

Exploring the Climate Change Impact on Major Food Crops of Bangladesh - A Time Series Analysis

This paper tries to explore the dynamic relationship between the yield of major crops in Bangladesh (aus, amas, boro, wheat and potato) and climate change (average rainfall, average maximum temperature and average minimum temperature). Graphical visualization shows that, there is increasing trend in average annual minimum temperature and average annual minimum rainfall, while there is decreasing trend of average annual maximum temperature. We applied autoregressive distributive lag (ARDL) cointegration method in order to study the dynamic relationship. The paper finds long run dynamic link between yield of aus rice and average rainfall and average minimum temperature. We have found short run dynamic relationship for yield of aman rice, boro rice and potato. However, we do not find any dynamic relationship has been found for yield of wheat with the variables of climate change. After estimation the dynamic relationship, we ensure there is no serial correlation among residuals using Breusch-Godfrey test and models are normally distributed using histogram and Jarque-Bera test. Finally, we ensure the stability of the models applying CUSUM test.

Climate Change Variability Analysis in and around Jinka, Southern Ethiopia. With Special Emphasis on Temperature and Rainfall

Purpose: Climate variability is a serious problem affecting the livelihoods of farmers in developing countries particularly those depend on rain fed agriculture. This study was carried out to investigate the extent of climate variability by using temperature and rainfall as key variables.Research Method: In this study the annual rainfall and temperature data of forty six years (1970- 2015) were analyzed using descriptive statistics such as mean, std. error of mean, variance, range, coefficient of variation, minimum and maximum values.Findings: The result of the study revealed that monthly rainfall variability was high both in dry month (CV=0.48) and peak rain month (CV=0.51). The result showed that from 1970 to 2015 the annual rainfall increased (R2=0.001) whereas the mean annual maximum and minimum temperature increased by 0.3620c and 0.3360c respectively. The linear trend line analysis shows a slightly increasing average annual rainfall, maximum and minimum temperature. The mean annual temperature of the area varies from a mean minimum of 21.20c, to a maximum of 22.80c with average temperature of 21.63 over the last forty six years.Research Limitations: This research is based on temperature and rainfall data of the study area.Originality: This study has shown rainfall and temperature variability over the last forty six years in Jinka station. In order to manage rainfall and temperature variability related risks, all concerned stakeholders should have to take into consideration for climate variability adaptation and mitigation strategies in order to minimize all potential risks and losses in the future.

Climate Variation Assessment Based on Rainfall and Temperature in Ilorin Kwara State Nigeria

In recent times and across the globe, the concept of climate has gained much relevance because of its dynamic and complex nature and the significant influence it has on various aspects of the environment, including the increasing threat of global climate change. This study focuses on the assessment of climatic variation in Ilorin based on the variations in rainfall and temperature within the period 1980-2015. Time Series Analysis was used to determine the trend of rainfall and temperature within the period 1980-2015. The 5-Year Moving Average was used to smoothen the time series and to eliminate unwanted fluctuations. Linear Regression was used to estimate the value of variable Y (total rainfall or average minimum temperature), corresponding to a given value of variable X (time), while MAKESEN software was used to determine the temporal trend of rainfall indices within the study period. Furthermore, the study focused on the spatial variations of total rainfall and average minimum temperature in the study area. The result revealed that there is downward trend of 0.814 mm per year in the annual mean rainfall and also there is an upward trend of 0.029 per year in average annual minimum temperature and total annual maximum temperature has an upward trend of 0.01 mm per year. Thus, the rainfall is decreasing and temperature tends to increase. Key word: Climate variability, Rainfall, Temperature, Period, Temporal trend, Kwara state

Changes and variability of precipitation and temperature in the Guna Tana watershed, Upper Blue Nile Basin, Ethiopia

This paper studied the spatial and temporal variability of the statistical structures of precipitation Guna Tana watershed, Upper Blue Nile, Ethiopia, by analyzing the time series of temperature and precipitation from six weather stations during the period from 1990 to 2016. Inverse distance weight, precipitation concentration index and MK test statics were used to detect annual and seasonal precipitation concentrations and the associated spatial patterns. The results show that precipitation concentration index values were mainly observed in Guna Tana watershed in which about 83.33% and 16.67% were the uniform concentration of precipitation and strong irregularity of precipitation distribution was observed in the kiremt seasons’ rainfall. The demonstration using Mann–Kendall trend test depicted that most parts of Guna Tana watershed are characterized by variability of precipitation and temperature. The results reveal that significant trends in average rainfall were observed (both positive and negative trends). Those significantly decreasing trends of average monsoon rainfall have the highest value of decreasing slope (i.e., − 1.88 mm/year) for Luwaye station and percentage change of − 31.07% in Bega season. Decreasing slopes (− 0.14 °C/year) and percentage change (− 22.79%) were observed in Luwaye station at the average annual minimum temperature and increasing Sen’s slope temperature recorded at 24.64 °C/year and percentage changes at 0.136% in 10% level of significance at Woreta station in average annual minimum temperature.

Winter hardiness of Miscanthus (III): Genome‐wide association and genomic prediction for overwintering ability in Miscanthus sinensis

AbstractOverwintering ability is an important selection criterion for Miscanthus breeding in temperate regions. Insufficient overwintering ability of the currently leading Miscanthus biomass cultivar, M. ×giganteus (M×g) ‘1993–1780', in regions where average annual minimum temperatures are −26.1°C (USDA hardiness zone 5) or lower poses a pressing need to develop new cultivars with superior cold tolerance. To facilitate breeding of Miscanthus, this study characterized phenotypic and genetic variation of overwintering ability in an M. sinensis germplasm panel consisting of 564 accessions, evaluated in field trials at three locations in North America and two in Asia. Genome‐wide association (GWA) and genomic prediction analyses were performed. The Korea/N China M. sinensis genetic group is a valuable gene pool for cold tolerance. The Yangtze‐Qinling, Southern Japan, and Northern Japan genetic groups were also potential sources of cold tolerance. A total of 73 marker–trait associations were detected for overwintering ability. Estimated breeding value for overwintering ability based on these 73 markers could explain 55% of the variation for first winter overwintering ability among M. sinensis. Average genomic prediction ability for overwintering ability across 50 fivefold cross‐validations was high (~0.73) after accounting for population structure. Common genomic regions for overwintering ability were detected by GWA analyses and a previous parallel QTL mapping study using three interconnected biparental F1 populations. One QTL on Miscanthus LG 8 encompassed five GWA hits and a known cold‐responsive gene, COR47. The other overwintering ability QTL on Miscanthus LG 11 contained two GWA hits and three known cold stress‐related genes, carboxylesterase 13 (CEX13), WRKY2 transcription factor, and cold shock domain (CSDP1). Miscanthus accessions collected from high latitude locations with cold winters had higher rates of overwintering, and more alleles for overwintering, than accessions collected from southern locations with mild winters.

Winter hardiness of Miscanthus (II): Genetic mapping for overwintering ability and adaptation traits in three interconnected Miscanthus populations

AbstractMiscanthus × giganteus (M×g) is the primary species of Miscanthus for bioenergy feedstock production. The current leading biomass cultivar, M×g ‘1993‐1780’, is insufficiently adapted in temperate regions with cold winters such as USDA hardiness zone 5 (average annual minimum temperature of −28.9 to −23.3°C) or lower. Three interconnected Miscanthus F1 populations that shared a common parent were planted in a replicated field trial at Urbana, IL (hardiness zone 5b; average annual minimum temperature of −26.1 to −23.3°C) in spring 2011. The winter of 2013–2014 was especially cold in Urbana, with a minimum soil temperature at 10 cm of −6.2°C and a minimum air temperature of −25.3°C, giving us an opportunity to evaluate hardiness on established year‐3 plants. The parent in common to all three populations, M. sinensis ssp. condensatus ‘Cosmopolitan’, is native to maritime southern Japan, and in Urbana, it is winter‐damaged most years. In contrast, the three other parents, M. sacchariflorus ‘Robustus’ (MapA), M. sinensis ‘Silberturm’ (MapB), and M. sinensis ‘November Sunset’ (MapC), are typically winter hardy in Urbana. Nearly all MapA progeny plants survived and grew vigorously in spring 2014, whereas in MapB and MapC, many progeny plants did not survive the winter, and most of the survivors were severely damaged, with poor vigor. Negative correlations between overwintering ability and spring regrowth date and autumn dormancy date suggested that the genotypes most likely to survive winters were those that emerged early in spring and/or went dormant early in autumn. Using joint‐population analysis, we identified 53 quantitative trait loci (QTLs) for nine adaptation traits, including nine QTLs for overwintering ability and 11 for spring hardiness scores. Many biologically intuitive candidate genes were observed within or near the QTLs detected in this study, suggesting their validity and potential for further study.

Winter hardiness of Miscanthus (I): Overwintering ability and yield of new Miscanthus ×giganteus genotypes in Illinois and Arkansas

AbstractMiscanthus ×giganteus (M×g) is an important bioenergy feedstock crop. However, biomass production of Miscanthus has been largely limited to one sterile triploid cultivar, M×g ‘1993‐1780’, which we demonstrate can have insufficient overwintering ability in temperate regions with cold winters. Key objectives for Miscanthus breeding include greater biomass yield and better adaptation to different production environments than M×g ‘1993‐1780’. In this study, we evaluated 13 M×g genotypes, including ‘1993‐1780’, in replicated field trials conducted for three years at Urbana, IL; Dixon Springs, IL; and Jonesboro, AR. Entries were phenotyped for first‐winter overwintering ability and plant hardiness (ratio of new tillers to old), yield in years 2 and 3, and first heading date, plant height, and culm number in years 1 and 2. We observed substantial variation for overwintering ability and biomass yield among the M×g genotypes tested and identified ones with better overwintering ability and/or higher biomass yield than ‘1993‐1780’. Most entries at Urbana were damaged during the first winter, whereas few or no entries were damaged at Dixon Springs or Jonesboro. However, M×g ‘Nagara’ was entirely undamaged during the first winter and produced high biomass yields at Urbana (19.7 Mg/ha in year 2 and 20.9 Mg/ha in year 3), whereas M×g ‘1993‐1780’ exhibited an overwintering loss of 29%, had severely damaged survivors (hardiness score of 25%), and reduced biomass yield (8.1 Mg/ha in year 2 and 16.2 Mg/ha in year 3), indicating that M×g ‘Nagara’ could be a better choice in hardiness zone 5 (average annual minimum air temperature of −23.3 to −28.9°C) or lower. In Dixon Springs, where M×g ‘1993‐1780’ was undamaged by the first winter, it yielded highest among all the entries (21.6 Mg/ha in year 3), though not significantly higher than M×g ‘Nagara’ (18.2 Mg/ha in year 3).

Observed trends in climate extremes over Bangladesh from 1981 to 2010

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 77:45-61 (2019) - DOI: https://doi.org/10.3354/cr01539 Observed trends in climate extremes over Bangladesh from 1981 to 2010 Md. Jamal Uddin Khan, A. K. M. Saiful Islam*, Mohan Kumar Das, Khaled Mohammed, Sujit Kumar Bala, G. M. Tarekul Islam Institute of Water and Flood Management, Bangladesh University of Engineering and Technology (BUET), Dhaka 1000, Bangladesh *Corresponding author: saiful3@gmail.com ABSTRACT: Bangladesh regularly faces various extreme events (floods, droughts, cyclones, and heat waves), but there is a knowledge gap between average climate and climate extremes over the country. The purpose of this study is to quantify the trends over Bangladesh for the period 1981-2010 using the extreme temperature and precipitation indices developed by the CCl/WCRP/JCOMM Expert Team on Climate Change Detection and Indices. We used precipitation and temperature data from 26 meteorological stations, calculated trends in the indices using Sen’s slope estimator, and tested significance using the non-parametric Mann-Kendall trend test. For the temperature indices, we found an overall increasing warming trend. Average annual maximum and minimum temperatures increased by 0.3 and 0.4°C decade-1 respectively. A faster rise of both maximum and minimum temperature was found compared with previous studies. The frequency of warm days increased by 12 days decade-1. The frequency of warm (cold) nights increased (decreased) by 7 (11) days decade-1. The overall warming was accelerated at the end of the climatic period (2001-2010). Precipitation indices showed an overall decreasing trend, in contrast to other studies in this region. Trends in consecutive dry days (CDD) indicated a drying tendency at a rate of 10 days decade-1. A decreasing rate of about 84 mm decade-1 was observed in annual average total precipitation. Except for CDD, most of the precipitation trends were statistically not significant and spatially incoherent. Statistically significant change was observed in extreme temperature events, with a strong and consistent spatial pattern. Our results pave the way for further investigations into future changes using results from climate simulations. KEY WORDS: Extreme indices · Expert Team on Climate Change Detection and Indices · ETCCDI · Bangladesh · Observed records · Climate change Full text in pdf format Supplementary material PreviousNextCite this article as: Khan MJU, Islam AKMS, Das MK, Mohammed K, Bala SK, Islam GMT (2019) Observed trends in climate extremes over Bangladesh from 1981 to 2010. Clim Res 77:45-61. https://doi.org/10.3354/cr01539 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 77, No. 1. Online publication date: January 08, 2019 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2019 Inter-Research.

乌伊岭国家级自然保护区植被覆盖演变及其对气候突变的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 乌伊岭国家级自然保护区植被覆盖演变及其对气候突变的响应 DOI: 10.5846/stxb201801310264 作者: 作者单位: 哈尔滨师范大学,哈尔滨师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41671100） Evolution of vegetation coverage and its response to abrupt climate change in the Wuyi Mountains National Nature Reserve Author: Affiliation: Harbin Normal University,Harbin Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:探究中国北方高纬度森林覆盖区植被演变受到气候因子变化乃至突变的影响，选用MODIS-NDVI数据与TM/ETM+数据，结合62年的气象观测数据，运用像元二分法模型、累计距平分析、Mann-Kendall非参数检验、滑动T检验与相关性分析，探讨了乌伊岭国家级自然保护区1975-2016年气候变化及其突变对植被覆盖的演化规律，并对不同气候因子与植被覆盖类型的空间变化进行相关性分析。结果表明：（1）乌伊岭保护区气候变化呈现暖干化发展的趋势。年均气温上升（0.557℃/10a），年均最低气温与冬季增温幅度最快，秋季最慢。降水量年际变化较小（-14.052 mm/10a），季节性变化明显。经突变性检验，1980-1995年是气候增温减湿的突变时期。（2）研究区植被生长季的NDVI为0.673，有植被覆盖的区域占87.69%，其中高等植被覆盖区所占比最大。（3）气候突变时期，生长季NDVI显著下降，植被退化严重。低植被覆盖区无显著变化，而高植被覆盖区开始逐渐退化为中等与中低等植被覆盖区。在空间上植被覆盖的退化状况主要由中心山地沿四周低山丘陵区累年逐渐降低。不同植被覆盖区域下降的幅度：混交林 > 草地 > 针叶林 > 耕地 > 湿地。（4）乌伊岭保护区年均最大NDVI与年均气温和年均降水量的相关系数分别为0.261、0.068，其中呈正相关区域占总面积56.67%和42.79%，在分布趋势上两者都表现出明显的空间差异性。而气温因子影响植被覆盖的空间范围与能力更强，空间相关性更高，也是影响植被退化的主导因素。 Abstract:To explore the influence of climatice factor changes and even mutations on vegetation evolution in high-latitude forest cover areas in northern China,we used MODIS-NDVI data and TM/ETM+ data, combined with a 62-year meteorological observation dataset, We analyzed these data using a pixel dichotomous model, cumulative anomaly analysis, a Mann-Kendall non-parametric test, sliding t-test, and correlation analysis. We discussed the evolution of climate change and its mutations on vegetation cover in the Wuyi Mountains National Nature Reserve from 1975 to 2016, as well as different climatic factors and vegetation cover types. The spatial variation was correlated. The results showed that:(1) Climate change in the Wuyi Mountains protected area exhibited a trend of warm and dry development. The annual average temperature increased (0.557℃/10a), the annual average minimum temperature and winter temperature increased fastest, whereas the autumn increase was the slowest. The annual variation in precipitation was small (-14.052mm/10a); however, the seasonal variation was obvious. Through the mutation test, 1980-1995 was a period of sudden change in climate warming and dehumidification. (2) The NDVI of the vegetation growing season in the study area was 0.673, and the area covered by vegetation accounted for 87.69%, of which the highest vegetation coverage area accounted for the largest proportion. (3) During the abrupt climate change period, NDVI decreased significantly during the growing season, and vegetation degradation was severe. There was no significant change in the low vegetation coverage area, and the high vegetation coverage area began to gradually degenerate into medium and low-level vegetation coverage areas. The degradation of vegetation cover in space was mainly reduced in the central mountainous areas along the low hills and surrounding areas. The extent of decline in different vegetation coverage areas was as follows:mixed forest > grassland > coniferous forest > cultivated land > wetland. (4) The correlation coefficient between annual average maximum NDVI and annual average temperature and annual average precipitation in the Wuyi Mountains protected area was 0.261 and 0.068, respectively, and the positive correlation area accounted for 56.67% and 42.79% of the total area, respectively. Significant spatial differences were observed. The temperature factor affecteds the spatial extent and capacity of vegetation coverage, and had a higher spatial correlation, which was also the dominant factor affecting vegetation degradation. 参考文献 相似文献 引证文献

Impacts of land use/land cover detection on climate variability of Gumara Watershed, Ethiopia

Land use/land cover (LU/LC) detection on climate variability has been conducted using satellite image and weather data in the study area. LU/LC analysis was done using supervised classification and the categories used were built-up area, forest, grassland, agriculture and waterbody. From the analysis, built-up area is shown as increasing from 1997 to 2017. Climate variability assessment done using the Mann-Kendall and Sen's slope estimator shows that average annual maximum temperature and mean temperature have positive trends, average annual minimum temperature shows a decreasing trend. Annual rainfall showed positive trend in the Bega season and decreasing trends in, Belg season and Kiremt season. Percentage changes were observed as 0.4%, 2.4% and 2.6% for average annual minimum, maximum and average annual temperature, respectively. Average annual rainfall, in Bega season, Belg season and Kiremt seasons was −1.7%, 3.5%, 6.5% and −6.4% respectively. Hence percentage changes show LU/LC change affects climate.

Climate Suitability and Vulnerability of Winter Wheat Planting in Gansu under the Background of Global Warming

Winter wheat is the main food crop in China. Gansu Province is a traditional winter wheat growing area, and its planting range is limited by the thermal conditions of winter. The average temperature in Gansu Province increased by 0.28°C per decade, higher than the China’s and global average, and the warming in winter was more obvious. Therefore, it is necessary to study the climate suitability and vulnerability of winter wheat planting in Gansu. In this paper, the maximum entropy model Maxent and Arcgis software are used to select six major climatic factors including annual total radiation, annual precipitation, the warmest monthly average temperature, the coldest monthly average temperature, annual average temperature, and annual extreme minimum temperature, which construct winter wheat planting distribution-climate relationship model that studies the climate suitability and vulnerability of winter wheat during the period 1961-2015. Studies have shown that the average cold weather and annual extreme minimum temperature are the most important climatic factors affecting winter wheat in Gansu, which can reflect the low temperature conditions that winter wheat can tolerate. However, the main winter wheat planting areas in Gansu Province are distributed in arid and semi-arid rain-fed agriculture areas. Precipitation and total annual radiation are also very important constraints. At the same time, climate change has little effect on winter wheat in Gansu Province, and the area of suitable area fluctuates slightly. It shows moderate adaptation in each evaluation period.

Climate variability and adaptation of Homegardens in South Asia: case studies from Sri Lanka, Bangladesh and India

This study assessed the climate variability, vulnerability of Homegardens (HGs), and elements that influence the adaptation decisions of homegardeners in selected regions in South Asia. Study sample comprised 148 HGs in three sites in Sri Lanka, 120 HGs in Bangladesh and 100 HGs in India. Variability in temperature and rainfall in the sites from 1961 to 2010, and changes in the onset of cultivating seasons during two decades (1991-2010) were analyzed. The socio-economic data of the homegardeners, agronomic data of HGs, diversity of trees and farm animals, and adaptation strategies used in HGs for perceived variability in climate during 1991-2010 were collected using a questionnaire survey. The annual rate of rise in night-time minimum temperature in the three Sri Lankan study sites (0.012 to 0.022 °C; R2 = 0.251 to 0.589; p&lt;0.05) and in the Indian study site (0.041 °C; R2 = 0.324; p&lt;0.05) more pronounced than the increase in day-time maximum temperature. The average annual day-time minimum and maximum temperatures in Bangladesh study site did not show a significant variation (p&gt;0.05). The annual cumulative rainfall did not reveal any discernible trend in all study sites (p&gt;0.05). From 1991-2010, 85 % of Maha seasons in Sri Lanka (September to February) have not been set on time (p&lt;0;05), whereas in Bangladesh and Indian study sites, the onset of the majority of cultivating seasons was not delayed. The HGs in Sri Lankan sites were mainly crop-based while those from India and Bangladesh had a rich blend of crops and farm animals. The homegardeners have made changes to planting dates of annual crops, agronomic practices, technology used (new annual crop varieties and irrigation equipment) and soil and water conservation measures to adapt to climate variability. Probit analysis showed that the type of employment, age, education level of the household head, experience in farming, HG size (extent), presence of farm animals and tree density of the HGs have significantly influenced the decision of homegardeners to adopt any adaptation strategy. Homegardeners who perceived climate variability were more adaptable and adaptation strategies were location specific.

Forest biomass-carbon variation affected by the climatic and topographic factors in Pearl River Delta, South China

Subtropical forests function as important carbon sinks for atmospheric CO2. Nonetheless, there remain uncertainties about the effects of climate and topography on subtropical forest biomass-carbon stocks. A continuous biomass expansion factor (BEF) method was applied to forest inventory data to estimate biomass-carbon storage and carbon sink rate, and their changes along with abiotic and biotic factors in the Pearl River Delta (PRD) of South China. BEF equations were built using a set of field-based data. Biomass-carbon increased from 62.92 to 70.56 Mt along with forest growth and increasing forest area during the latest two periods of the national forest inventory (2004-8 and 2009-13). The PRD's forests continued to be net carbon sinks 0.51 t ha−1 yr−1. The PRD's forests have a high potential as biomass-carbon sinks in the future, because 46.75% of the forests are at the young or middle-aged stage. In addition, principal component analysis indicated that both biomass-carbon density and carbon sink rate were positively correlated with the area percentage of mature and over-mature forests, average annual precipitation and minimum temperature, but they were negatively correlated with average annual maximum temperature. Pearson correlation analysis demonstrated that biomass-carbon density and carbon sink rate affected by average altitude, while they were not related to the slope angle.

Trends of climate change indices in some Mexican cities from 1980 to 2010

Global studies focusing on climate extremes in urban areas, specifically in Mexico, have not been approached with a sufficient level of detail, despite considerably increased risks for both infrastructure and human society. Based on 14 climate indices proposed by the Expert Team on Climate Change Detection and Indices (ETCCDI) and the application of the nonparametric Mann-Kendall and Sen’s slope tests, the observed trends of climate extremes in 16 urban areas in Mexico from 1980 to 2010 were analyzed. The results show that climate conditions over most cities of Mexico are changing, as indicated by a warming trend during the study period. Significant increases were detected in the annual average maximum temperature (TMX) and the annual average minimum temperature (TMN). There is no clear trend that the warmest days (TXx) are increasing, but the annual number of warm days (TX90p) and summer days (SU) has increased, and the cold days (TX10p) have decreased. Associated with these changes are concomitant decreases in fewer coldest nights (TNn), an increase in the percentage of days with warm nights (TN90p) and tropical nights (TR), and a decrease in the number of frost days (FD). In contrast, the analysis reveals a statistically significant decrease in the mean temperature and the amount of warm days in Mexico City, which could be associated with the increasing trend of atmospheric pollution and the continuous smoke and ash emissions from the volcano Popocatepetl, which disperse incoming solar radiation and reduce radiative forcing. Climate change indices based on daily precipitation data show positive trends in many cities. In general, an increasing trend in very wet days (R95p), a number of very heavy rainfall days ≥ 25 mm (R25), and the annual total wet days (PRCP) were observed. These results highlight the vulnerability of cities confronted with both global and local climate change and the importance of promoting effective local risk reduction measures as part of urban planning for city dwellers.