Climate Services Using IMDAA Data and Web Development Tools: Visualization and Analysis of Temperature and Precipitation Trends over India

Coweeta Hydrologic Laboratory, located in western North Carolina, USA, is a 2,185 ha basin wherein forest climate monitoring and watershed experimentation began in the early 1930s. An extensive climate and hydrologic network has facilitated research for over 75 years. Our objectives in this paper were to describe the monitoring network, present long-term air temperature and precipitation data, and analyze the temporal variation in the long-term temperature and precipitation record. We found that over the period of record: (1) air temperatures have been increasing significantly since the late 1970s, (2) drought severity and frequency have increased with time, and (3) the precipitation distribution has become more extreme over time. We discuss the implications of these trends within the context of regional and global climate change and forest health.

Determination of spatial and temporal patterns of precipitation and drought remains a challenge in many arid and semi-arid regions. Generally, in these areas, precipitation measurements obtained from field stations are few or unreliable. Reanalysis precipitation data has opened up new large-scale hydrological application in data-sparse or ungauged catchments. This study presents a method based on GIS, statistical tests, and satellite-based precipitation for the analysis of spatial and temporal precipitation and drought trends. As a case study, we used 35 years (1979–2013) of precipitation data from the climate forecast system reanalysis (CFSR) for the Mexican state of Durango. For trend detection, we used the statistical test of Mann–Kendall at 5% standard precipitation index timescale of 12 months (SPI-12) to analyze the spatiotemporal trends of drought, and principal component analysis (PCA) was applied to characterize the spatial patterns. In many of the grid locations analyzed, the precipitation trends were not statistically significant. However, the months within winter and spring, except for June, showed a decreasing trend in precipitation, while the months of July, August, and September showed an increasing trend. This variation in rainfall intensity agrees with the climate pattern reported for this region. The frequency of drought events for each month during the period of analysis was mapped. The incidence of drought events was higher in June and September. Drought events are present all around the state of Durango, but they are more frequent in the northern part, in the Sierra Madre Occidental, Mapimi, and Laguna regions.

Various remote sensing products and observed data sets were used to determine spatial and temporal trends in climatic variables and their relationship with snow cover area in the higher Himalayas, Nepal. The remote sensing techniques can detect spatial as well as temporal patterns in temperature and snow cover across the inaccessible terrain. Non-parametric methods (i.e. the Mann–Kendall method and Sen's slope) were used to identify trends in climatic variables. Increasing trends in temperature, approximately by 0.03 to 0.08 °C year−1 based on the station data in different season, and mixed trends in seasonal precipitation were found for the studied basin. The accuracy of MOD10A1 snow cover and fractional snow cover in the Kaligandaki Basin was assessed with respect to the Advanced Spaceborne Thermal Emission and Reflection Radiometer-based snow cover area. With increasing trends in winter and spring temperature and decreasing trends in precipitation, a significant negative trend in snow cover area during these seasons was also identified. Results indicate the possible impact of global warming on precipitation and snow cover area in the higher mountainous area. Similar investigations in other regions of Himalayas are warranted to further strengthen the understanding of impact of climate change on hydrology and water resources and extreme hydrologic events.

Changes in climate during the 20th century differ from region to region across the United States. We provide strong evidence that spatial variations in US temperature trends are linked to the hydrologic cycle, and we also present unique information on the seasonal and latitudinal structure of the linkage. We show that there is a statistically significant inverse relationship between trends in daily temperature and average daily precipitation across regions. This linkage is most pronounced in the southern United States (30-40 degrees N) during the May-June time period and, to a lesser extent, in the northern United States (40-50 degrees N) during the July-August time period. It is strongest in trends in maximum temperatures (T(max)) and 90th percentile exceedance trends (90PET), and less pronounced in the T(max) 10PET and the corresponding T(min) statistics, and it is robust to changes in analysis period. Although previous studies suggest that areas of increased precipitation may have reduced trends in temperature compared with drier regions, a change in sign from positive to negative trends suggests some additional cause. We show that trends in precipitation may account for some, but not likely all, of the cause point to evidence that shows that dynamical patterns (El Niño/Southern Oscillation, North Atlantic Oscillation, etc.) cannot account for the observed effects during May-June. We speculate that changing aerosols, perhaps related to vegetation changes, and increased strength of the aerosol direct and indirect effect may play a role in the observed linkages between these indices of temperature change and the hydrologic cycle.

The Chitwan Annapurna Landscape (CHAL) is the central part of the Himalayas and covers all bioclimatic zones with major endemism of flora, unique agro-biodiversity, environmental, cultural and socio-economic importance. Not much is known about temperature and precipitation trends along the different bioclimatic zones nor how changes in these parameters might impact the whole natural process, including biodiversity and ecosystems, in the CHAL. Analysis of daily temperature and precipitation time series data (1970–2019) was carried out in seven bioclimatic zones extending from lowland Terai to the higher Himalayas. The non-parametric Mann-Kendall test was applied to determine the trends, which were quantified by Sen’s slope. Annual and decade interval average temperature, precipitation trends, and lapse rate were analyzed in each bioclimatic zone. In the seven bioclimatic zones, precipitation showed a mixed pattern of decreasing and increasing trends (four bioclimatic zones showed a decreasing and three bioclimatic zones an increasing trend). Precipitation did not show any particular trend at decade intervals but the pattern of rainfall decreases after 2000AD. The average annual temperature at different bioclimatic zones clearly indicates that temperature at higher elevations is increasing significantly more than at lower elevations. In lower tropical bioclimatic zone (LTBZ), upper tropical bioclimatic zone (UTBZ), lower subtropical bioclimatic zone (LSBZ), upper subtropical bioclimatic zone (USBZ), and temperate bioclimatic zone (TBZ), the average temperature increased by 0.022, 0.030, 0.036, 0.042 and 0.051 °C/year, respectively. The decade level temperature scenario revealed that the hottest decade was from 1999–2009 and average decade level increases of temperature at different bioclimatic zones ranges from 0.2 to 0.27 °C /decade. The average temperature and precipitation was found clearly different from one bioclimatic zone to other. This is the first time that bioclimatic zone level precipitation and temperature trends have been analyzed for the CHAL. The rate of additional temperature rise at higher altitudes compared to lower elevations meets the requirements to mitigate climate change in different bioclimatic zones in a different ways. This information would be fundamental to safeguarding vulnerable communities, ecosystem and relevant climate-sensitive sectors from the impact of climate change through formulation of sector-wise climate change adaptation strategies and improving the livelihood of rural communities.

This study examined temperature and precipitation trends and spatial variations over a 40-year period at 34 meteorological stations in Bangladesh. Climate variability was assessed using a variety of statistical techniques, such as geographic information systems (GIS), inverse distance weighting (IDW) interpolation, linear regression, and coefficient of variation. The temperature and precipitation data were simulated using an autoregressive integrated moving average (ARIMA) model. With an average temperature increase of 0.20 °C every ten years, the results showed a significant warming trend. Northern, central, and southern regions saw the largest increases in minimum temperatures (from 0.80 to 2.4 °C), while southern and southeastern regions saw the largest increases in maximum temperatures (1.20 to 2.48 °C). Although pre-monsoon and post-monsoon rainfall showed declines of 0.75 mm and 0.55 mm per year, respectively, with significant variability in these seasons (44.84% and 85.25%, respectively), annual precipitation showed an upward trend (+7.13 mm per year). Projections for 2011–2020 suggest a temperature rise of 0.018 °C annually, potentially resulting in a 1.0 °C increase compared to 1971. Minimum temperatures are expected to rise more sharply (0.20 °C) than maximum temperatures (0.16 °C). Annual precipitation is predicted to decrease by 153 mm, with drying conditions anticipated in northwestern, western, and southwestern regions during pre- and post-monsoon periods.

Precipitation is one of the most variable climatic parameters, as it is determined by many physical processes. The spatiotemporal characteristics of precipitation have been significantly affected by climate change during the past decades. Analysis of precipitation trends is challenging, especially in regions such as Greece, which is characterized by complex topography and includes several ungauged areas. With this study, we aim to shed new light on the climatic characteristics and inter-annual trends of precipitation over Greece. For this purpose, we used ERA5 monthly precipitation data from 1950 to 2020 to estimate annual Theil–Sen trends and Mann–Kendall significance over Greece and surrounding areas. Additionally, in order to analyze and model the nonlinear relationships of monthly precipitation time series, we used generalized additive models (GAMs). The results indicated significant declining inter-annual trends of areal precipitation over the study area. Declining trends were more pronounced in winter over western and eastern Greece, but trends in spring, summer and autumn were mostly not significant. GAMs showcased that the trends were generally characterized by nonlinearity and precipitation over the study area presented high inter-decadal variability. Combining the results, we concluded that precipitation did not linearly change during the past 7 decades, but it first increased from the 1950s to the late 1960s, consequently decreased until the early 1990s and, afterwards, presented an increase until 2020 with a smaller rate than the 1950–1960s.

This study investigates whether a regional climate model (RCM) driven by a global general circulation model (GCM) in a nesting approach with observed atmospheric CO2 concentrations shows predictability for temperature and precipitation trends during 1961–1990 in the Mediterranean area, a region strongly influenced by large‐scale circulation. Resulting discrepancies between model and observations raise the question whether the model predictability increases after removing impacts of mid‐latitude circulation variability. For temperature and precipitation trends we use the RCM REMO and the observational dataset E‐OBS, and for atmospheric circulation the driving coupled GCM ECHAM5/MPI‐OM and NCEP/NCAR reanalyses. Cross‐validated multiple regression analyses between large‐scale circulation and regional temperature and precipitation are performed for observed and simulated data. The impact of circulation is removed from the original temperature and precipitation data, and the trends of circulation‐related and circulation‐unrelated parts are compared. The circulation‐related trends of models and observations show discrepancies owing to differing observed and simulated mid‐latitude circulation dynamics, i.e. different temporal evolutions of North Atlantic Oscillation and East Atlantic pattern in winter and East Atlantic Jet and a blocking pattern in summer. Such differences can be related to unknown initial conditions of GCM simulations. In fact, we find strong impacts of initial conditions on mid‐latitude circulation dynamics of ECHAM5/MPI‐OM ensemble members over 30‐year periods. The agreement between simulated and observed circulation‐unrelated trends is generally higher than for original trends indicating that the predictability of this nesting approach increases by removing impacts of mid‐latitude circulation variability. We conclude that initial conditions affect climate variability up to the multi‐decadal timescale, at least in parts of the globe which are governed by extratropical circulation modes, and hence, hinder the comparability of simulated and observed climate trends over time periods shorter than the timescale dominated by radiative forcing. In the Mediterranean Basin the latter is definitely beyond 30 years.

This study deals with the historical hydro-climatological watershed characteristics of the Litani basin located in Lebanon, east of the Mediterranean Sea, during 1900–2008. The basin is divided into two distinct sub-basins. The Upper Litani Basin (ULB) is mostly dominated by mountainous geophysical features and the Lower Litani Basin (LLB) is closer to the Mediterranean coast. Monthly and annual temperature and precipitation data were generated from different sources, including global gridded data, satellite data, and local station data. Because long-term runoff records were not available, previously generated monthly synthetic runoff data were employed. Temperature and precipitation trends were investigated using the Mann-Kendall and Sen Slope nonparametric trend tests. The mean annual and monthly runoff were subsequently correlated with temperature and precipitation variations using a multiple linear regression approach. The results show that between 1900 and 2008, the whole Litani basin, includ...

The North Atlantic Oscillation (NAO) is a large-scale climate teleconnection that coincides with worldwide changes in weather. Its impacts have been documented at large scales, particularly in Europe, but not as much at regional scales. Furthermore, despite documented impacts on ecological dynamics in Europe, the NAO’s influence on North American biota has been somewhat overlooked. This paper examines long-term temperature and precipitation trends in the southern Appalachian Mountain region—a region well known for its biotic diversity, particularly in salamander species—and examines the connections between these trends and NAO cycles. To connect the NAO phase shifts with southern Appalachian ecology, trends in stream salamander abundance are also examined as a function of the NAO index. The results reported here indicate no substantial long-term warming or precipitation trends in the southern Appalachians and suggest a strong relationship between cool season (November–April) temperature and precipitation and the NAO. More importantly, trends in stream salamander abundance are best explained by variation in the NAO as salamanders are most plentiful during the warmer, wetter phases.

<p>Precipitation and temperature changes across the Vakhsh and Panj basins are of great importance for Tajikistan, Afghanistan, Turkmenistan, and Uzbekistan for consumption, agricultural, and energy purposes. While studies of precipitation and temperature trends have been conducted in these basins, attention to their heterogenous topography and nature have not been considered and analyzed together with glacial and permafrost melt. Here, we assessed the trends of precipitation and temperature over the last 20 years using remote sensing products. For precipitation, we used research grade daily GPM IMERG V06 Final Run from 2001 to 2020. Similarly, temperature MODIS Land Surface Temperature & Emissivity (LST&E) (MOD11A1) was used to assess temperature trends and separate liquid from solid precipitation. Annual precipitation and temperature trends were also assessed in three elevation bands: low (317-2225m), middle (2225-4500m) and high (4500-7543m).</p><p>Positive significant trends for solid precipitation mainly arise in the northern parts of the basins, while slightly positive with more negative trends occurred over the central and southern parts of the Panj basin. A significant solid precipitation trend of +1.30mm y<sup>-1</sup> below 2225 m a.s.l. occurred in late spring. Many of the pixels (1 x 1 km) across the study region that exhibited significant trends were increases in temperature, especially in the high elevations in the eastern portion of the basins. There was a significant annual increase of liquid precipitation coupled with a decrease in solid precipitation and an increase in temperature trend in the central Pamirs, implying a shift from solid to liquid precipitation. An increase in rainfall below 4500 m a.s.l. was observed, where the largest increases occurred in the western portions of these basins with nearly no significant temperature trends; thus, potentially having a positive influence on agricultural and community water supplies. However, long-term water supplies in the dry regions of the central and eastern parts of the basins may create supply vulnerabilities.</p>

Climate warming is projected to result in increases in total annual precipitation in northeastern North America. The response of runoff to increases in precipitation is likely to be more complex because increasing evapotranspiration (ET) could counteract increasing precipitation. This study was conducted to examine these competing trends in the historical record for 22 rivers having >70 yr of runoff data. Annual (water year) average precipitation increased in all basins, with increases ranging from 0.9 to 3.12 mm yr−1. Runoff increased in all basins with increases ranging from 0.67 to 2.58 mm yr−1. The ET was calculated by using a water balance approach in which changes in terrestrial water storage were considered negligible. ET increased in 16 basins and decreased in 6 basins. Temporal trends in temperature, precipitation, runoff, and ET were also calculated for each basin over their respective periods of record for runoff and for the consistent period (1927–2011) for the area-weighted average of the nine largest non-nested basins. From 1927 through 2011, precipitation and runoff increased at average rates of 1.6 and 1.7 mm yr−1, respectively, and ET increased slightly at a rate of 0.18 mm yr−1. For the more recent period (1970–2011), there was a positive trend in ET of 1.9 mm yr−1. The lack of a more consistent increase in ET, compared with the increases in precipitation and runoff, for the full periods of record, was unexpected, but may be explained by various factors including decreasing wind speed, increasing cloudiness, decreasing vapor pressure deficit, and patterns of forest growth.

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 43:179-190 (2010) - DOI: https://doi.org/10.3354/cr00909 Trends in temperature and precipitation on the Tibetan Plateau, 1961–2005 Heli Lu1,2,*, Guifang Liu1 1Institute of Natural Resources and Environmental Science, and College of Environment and Planning, Henan University, Kaifeng 475004, China 2United Nations University - Institute of Advanced Studies, Yokohama 220-8502, Japan *Email: cluheli@gmail.com ABSTRACT: We studied the basic characteristics of temperature and precipitation in different climatic zones of the Tibetan Plateau (TP) from 1961–2005, through statistical and spatial analysis. Over the past 45 yr, annual temperature in the TP increased at a rate of 0.265°C decade–1. The rate of temperature increase in winter was double that of spring in almost all zones and the rate of annual temperature increase was demonstrably higher during 1980–2005 than during 1961–1980 and 1961–2005, suggesting that the rate of warming is accelerating. Annual precipitation showed a slight increase (8.21 mm decade–1) across the whole TP. Short (2 to 4 yr), middle (5 to 8 yr), and long (>10 yr) precipitation cycles were found at 32, 11, and 6 stations, respectively. Empirical Orthogonal Function (EOF) analysis revealed different precipitation cycles between the northern and the southern TP, with the boundary along 33°N. For the period 1961–2005, 46 stations showed a warming-wetting trend; the number of stations showing this trend for 1980–2005 was 34% higher than for 1961–1980, suggesting that a warming-wetting trend will dominate the TP in the future. KEY WORDS: Tibetan Plateau · Basic characteristics · Climatic zones Full text in pdf format PreviousNextCite this article as: Lu H, Liu G (2010) Trends in temperature and precipitation on the Tibetan Plateau, 1961–2005. Clim Res 43:179-190. https://doi.org/10.3354/cr00909 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 43, No. 3. Online publication date: October 19, 2010 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2010 Inter-Research.

依据国家气象局提供的实测月降水和日降水资料,运用Mann-Kendall(M-K)非参数检验法验证了降水趋势,并通过空间插补法,由点扩展到面,分析了1990s长江流域降水变化特征,发现1990s长江流域降水变化以降水在时间和空间分布上的集中度的增加为主要特点:时间上,年降水的增加趋势以冬季1月和夏季6月降水的集中增加为主;一日降水量大于等于50mm的暴雨日数和暴雨量在1990s也有了较明显的增加.空间上,年降水、夏季降水、冬季降水的增加都以中下游区的增加为主,尤其以鄱阳湖水系、洞庭湖水系的降水增加为主.1990s长江流域春季和秋季降水的减少以5月和9月两个汛期月份的降水减少为主,除金沙江水系和洞庭湖水系等少数地区外,流域大部分地区降水呈减少趋势.上述1990s出现的降水趋势明显与近年来全球变暖背景下长江流域各地区不同的温度及水循环变异有关.;Applying with Mann-Kendall statistical method and IDW interpolation method, the precipitation trends in 1990s in the Yangtze River catchment were analysed based on the monthly and daily precipitation data provided by National Meteorology Administration of China. The results show:(1) The precipitation trends in the Yangtze River catchment are characterized by concentration on temporal and spatial distribution. Precipitation increases in January (winter) and in June (summer) contribute most to yearly precipitation increment; days with rainstorm and magnitude of rainstorm are increased evidently in 1990s compared with time period 1951-1990; the yearly, summer and winter precipitation trends are positive in most part of the middle and lower reaches of Yangtze River, especially in Poyang Lake basin and Dongting Lake basin. (2) Precipitation decreases in May and in September contribute most to spring precipitation decrement and autumn precipitation decrement, except for regions in Jinshajiang River basin and Dongting Lake basin; the precipitation in spring and autumn in the whole catchment shows negative trends in 1990s approximately.

Analysis of Average Annual Rainfall and Average Maximum Annual Temperature for a Period of 30 years to Establish Trends in Kieni, Central Kenya