Trend In Mean Annual Temperature Research Articles

Reconstruction of temperature and monsoon precipitation in southwestern China since the last deglaciation

Monsoon precipitation and temperature are the crucial components of the Indian monsoon climate, yet their spatial-temporal relationship remains unclear. In this study, we reconstruct the changes in monsoon precipitation and mean annual temperature simultaneously over the past 16,000 years using multiple proxies, including isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) and n-alkanes, from an alpine lake in southwestern China. On the one hand, the reconstructed monsoon precipitation shows a long-term increasing trend during the last deglaciation and a gradual decrease during the Holocene, with the highest-humidity period occurring in the early Holocene. Our result displays good consistency with the changes in regional mean annual precipitation, summer precipitation, and monsoon intensity during the last deglaciation and the Holocene. On the other hand, the reconstructed mean annual temperature inferred from the n-alkane proxy shows a long-term warm trend since the last deglaciation. Our result is consistent with the regional reconstruction of both mean annual and summer temperatures during the last deglaciation, while evident seasonal differences were observed for Holocene records with a cooling trend of summer temperature and a warm trend of mean annual temperature. Comprehensive comparison reveals that monsoon precipitation in the Indian monsoon region is mainly related to changes in the Intertropical Convergence Zone (ITCZ) and land-sea thermal contrast controlled by boreal summer insolation. In addition, the increase in temperature during deglaciation is primarily attributed to the escalation of greenhouse gases (GHGs), while the divergent trend of seasonal temperature during the Holocene is mainly attributed to the changes in local seasonal insolation. Our research emphasizes that monsoon precipitation is a summer signature in the Indian monsoon region, which is consistent with the changes in summer temperature, while contrasting with the changes in mean annual temperature. Therefore, it is necessary to consider the seasonal difference in temperature changes when investigating the hydrothermal combination in Indian monsoon regions.

Анализ многолетних трендов температуры в бассейне реки Кафирниган в Таджикистане

In this study, the trend and magnitudinal changes of monthly and annual temperature was determined by applying the non-parametric Mann-Kendall, modified Mann-Kendall, and Sen’s slope tests in the Kofarnihon River Basin. Also, Pettitt’s test was used to analyze the changes during the 1951–2012 and 1979–2012 time periods. The study revealed that the seasonal temperature trend decreased in winter and significantly increased in spring. The mean annual temperature trend at all six climate stations exhibited an increasing trend during 1951–2012-time period. The decadal temperature trend at all stations varied from 0.36 °C/decade at Isambay station and –0.18 °C/decade at Anzob station. Abrupt change points in air temperature occurred around the 1970s in the low altitude areas and in the high altitude areas occurred around 2000.

Climate change in the Debrecen area in the last 50 years and its impact on maize production

The average yield of maize is significantly dependent on the meteorological conditions of the growing year. Both the most favorable weather conditions and the weather anomalies that tend to cause damage depend on the given phenophase. The aim of this research is to analyze the climatic changes that are important in maize production in the Hajdúság region. For the climatological study of the area, homogenized temperature and precipitation data from the Hungarian Meteorological Service was used for the Debrecen region, which are freely available for download from the data repository of the institution. Trend analysis was performed for the last 50-year (1973–2022) and 30-year (1993–2022) periods. In total, 40 meteorological data series matching the study objective were analyzed. Linear regression calculations were performed using the SPSS 27 statistical software. For the non-parametric procedure, the MAKESENS Excel application was used, based on the Mann-Kendall (MK) test and Sen's slope estimation. This research shows that the choice of the length of the study period affects the results of trend analysis. The numerical values of the trend slope for the 30-year vs. 50-year period differ, and for some parameters there are also substantial differences (e.g., trend sign). The results of the parametric and non-parametric trend analyses differed only marginally for the temperature variables included. Also, for precipitation data that do not follow a normal distribution (e.g., monthly), there were only a few significant differences. The trend in mean annual temperature shows an increase of 0.39 and 0.52 °C in 10 years, and an increase of around 2 °C in 50 years and 1.5 °C in 30 years. There is a significant warming in both the summer and winter half-years, with the summer half-year showing a steeper upward trend in the 50-year data series and the winter half-year in the 30-year data series. There is a clear pattern of large, highly significant warming in the summer months and less significant changes in the two spring and two autumn months that were observed. A negative, non-significant trend in annual precipitation is observed. The decreases of 17 mm and 24 mm/10 years obtained for the 50- and 30-year time series are not negligible from a practical point of view. For the summer half-year, the precipitation amount is decreasing, with a slope of -27 mm/10 years for the last 30 years, but even this value is not significant due to the high variability. There is no significant change in the amount of precipitation in the winter half-year over the last decades. Significant trends cannot be detected from monthly or even semi-annual or annual precipitation data. The Mann-Kendall test showed a trend decrease only in the 30-year April data series at the p=0.1 significance level. Overall, the changes are negative for maize production. It should be highlighted that the obvious warming, combined with a slight decrease in precipitation, is leading to a deterioration in crop water availability and a reduction in crop yields. The impact of the identified adverse climatic changes can be compensated to a significant extent by the proposed agrotechnical responses.

Spatiotemporal trends in mean and extreme climate variables over 1981–2020 in Meki watershed of central rift valley basin, Ethiopia

Understanding the spatiotemporal changes of climate extremes is essential for managing climatic risk. In the present study, trends of annual and seasonal climate variables along with extreme temperature and precipitation were examined in eight climatic stations of Meki watershed, the Central Rift Valley Basin, Ethiopia during the period 1981 to 2020. A set of 20 precipitation and temperature extreme indices were selected and computed in RClimDex package of the R program to detect climate extreme events. The recent method of Innovative trend analysis, the non-parametric Mann–Kendall trend test, and Sen's slope estimator were applied to evaluate trends of the annual and seasonal precipitation and temperature. The result indicates that the annual precipitation has been decreasing in 71% of climatic stations and 43% of these stations showed a significant trend. The annual minimum temperature declined in 75% of the stations, whereas all stations indicated a significant increasing trend in annual mean maximum temperature. The Mann–Kendall test detected a significant increasing and decreasing trend in most of the temperature and precipitation extreme indices respectively. For the temperature extremes, more frequent warm and fewer cold temperature extremes were observed. In more than 75% of the climatic stations, a considerable drying trend was found for the precipitation extreme indices. Besides, stations with significant warming and drying trends were located in the downstream areas of the watershed. Overall, this study proved that the observed warming trend in mean annual temperature contributed to changes in the normal thresholds of extremes. The change in precipitation and temperature extremes have increased the frequency, intensity, and duration of extreme events in most of the stations. Likewise, climate extreme events that occur more frequently with high intensity are likely to exacerbate climatic risks, which require proper planning of risk management strategies in Meki watershed.

Changes in surface water dynamics across northwestern Canada are influenced by wildfire and permafrost thaw

The abundance and distribution of surface water at high latitudes is shifting rapidly in response to both climate change and permafrost thaw. In particular, the expansion and drainage of lakes and ponds is widespread but spatially variable, and more research is needed to understand factors driving these processes. In this study we used medium resolution (30 m) remote sensing data to analyse changes in lake area in permafrost-rich lowland regions across northwestern Canada. First, we used the Global Surface Water Dataset developed by the GLAD research group to map the absolute area of different land–water transitions across a 1.4 million km2 study domain. Next, we selected six regional study areas representing a range of climatic, geologic and hydrologic conditions. Within these regional study areas, we used the Landsat satellite archive to map annual trends in the area of 27 755 lakes between 1985 and 2020. We trained a random forests model to classify lakes exhibiting significant increasing or decreasing trends in area, and assessed the relative importance of climate, disturbance and environmental variables in determining the direction of change. Our analysis shows that significant increases in lake area were 5.6 times more frequent than decreases during the study period. Wildfire and ground ice abundance were the most important predictors of the direction of change. Greater ground ice content was associated with regions that experienced increases in lake area, while wildfire was associated with regions that experienced decreases in lake area. The effects of climate, including trends in mean annual temperature and total annual precipitation were smaller than disturbance and environmental factors, indicating that climate has likely had indirect effects on lake area changes over our period of study.

A locally relevant framework for assessing the risk of sea level rise under changing temperature conditions: Application in New Caledonia, Pacific Ocean

Sea level rise is a key feature in a warmer world and its impact can be seen globally. Assessing climate change-induced sea level rise, therefore, is urgently needed particularly in small island nations, where the threats of sea level rise are immediate, but the level of preparedness is low. Here, we propose a stochastic simulator to link changes in Mean Annual Temperature (MAT) to Mean Annual Sea Level (MASEL) at the local scale. This is through what-if scenarios that are developed based on the association between local temperature and sea level. The model can provide a basis for a bottom-up impact assessment by addressing limitations of applying large-scale projections in small islands and facilitating the accessibility of the impact assessment to stakeholders. For this purpose, we decompose the MAT and MASEL signals into their linear trend and autocorrelation components as well as independent and identically distributed residual terms. We further explore the association between trend and residual terms of MAT and MASEL. If such dependencies exist, scenarios of sea level can be synthesized based on the trend and residual terms of temperature. We use linear regression to link trends of MAT and MASEL, and copulas to formulate dependencies between residuals. This allows stochastic sampling of MASEL conditioned to trend and random variability in MAT. This framework is used for retrospective and prospective simulations of MASEL in Nouméa, the capital city of New Caledonia, the Pacific. We set up six different model configurations for developing the stochastic sampler, each including various parametric options. By selecting the best setup from each configuration, we provide a multi-model stochastic projection of MASEL, assuming the persistence in current long-term trend in MAT and MASEL. We demonstrate how such simulations can be used for a risk-based impact assessments and discuss sources of uncertainty in future projections.

Disequilibrium in Trait-Climate Relationships of Trees and Birds

Climate change is expected to drive changes in the structure of ecological assemblages, but these responses might show considerable time lags. If these lags are large, then the observed composition of assemblages will fall out of equilibrium with current climatic conditions. This disequilibrium has several expected signatures, including trends in the magnitude of climate relationships through time and stronger climate relationships across space than through time. Here, I describe spatial and temporal patterns of functional assemblage composition of birds and trees and ask whether there is evidence of disequilibrium between climate and functional assemblage structure. I used bird assemblage data from the Breeding Bird Survey (BBS) and tree data from the Forest Inventory and Analysis program (FIA), in both cases spanning the continental United States and covering the time period 1970-2016. To describe functional assemblage composition, I used the community weighted means of five functional traits for trees and six traits for birds, and fit linear models to explain the variation in composition through time and across space. For most traits, spatial relationships were much stronger than temporal relationships, consistent with lagged responses of assemblages to climate change. Several of the traits showed trends over the study period, in some cases associated with trends in mean annual temperature. Others showed dynamics in the spatial relationships between climate and trait values. For example, the mean clutch size of birds depended only weakly on temperature in the early study period, but the relationship became strongly negative by 2016. While precipitation was often an important predictor of spatial patterns of functional composition, it was typically weakly correlated with the temporal patterns. This likely reflects the fact that temperature experienced more consistent long-term trends over the study period, whereas large year-to-year fluctuations in precipitation prevent composition from ever coming into equilibrium with precipitation in a particular year. Overall, there was substantial evidence of disequilibrium between functional assemblage composition and climate.

Climate change drives glacier retreat in Bhaga basin located in Himachal Pradesh, India

This paper reports changes in different glaciers of Bhaga basin located in western Himalaya, from 1979 to 2017. Glacier boundaries were delineated through semi-automated approach using Landsat satellite imagery. The variation of glacier extent in different elevation zones, snout retreat and decadal changes are observed. Results show that the total area of glaciers was 238 in 1979, which reduced to 230.8 by 2017 (retreat rate 12 ). Glaciers at low elevation and smaller in size are retreating faster. Analysis of Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation data shows decreasing trend of annual precipitation (–2.724, 1951–2015) and increasing trend of mean annual temperature (0.021). The statistical analysis using Mann-Kendall and Sen’s slope tests, applied at different confidence interval demonstrates that climate change corresponds to deglaciation, and topography controls glacier recession in the basin.

Trends of the observed temperature and its variations in the Tamil Nadu State of India

In this study, the trends of the annual and seasonal temperature and its variations are explored in the Tamil Nadu State of India. In order to find the trend direction and the magnitude of change across the state during 1969–2016, the mean maximum temperature (MMaxT), mean minimum temperature (MMinT), and mean annual temperature (MAT) of 17 climatological stations are analyzed. Evidently, the increasing trends in MMaxT, MMinT, and MAT are observed at the majority of the stations. Approximately 82% of the total stations have shown a significant positive trend in MAT and MMaxT at the 95% confidence level. The MAT has increased up to 1.4 °C with a variation in the rate of change from 0.01 to 0.29 °C per decade. MMaxT has shown a significant increase with a variation in the rate of change from 0.01 to 0.54 °C per decade for the last 47 years. However, MMinT has shown an increasing trend in 13 stations and a decreasing trend in 4 stations with a variation in the rate of change from − 0.05 to 0.31 °C per decade. In the recent decades, the majority of the stations have experienced high warm and the year 2016 is observed to be the warmest year. Based on a spatial scale, temperature differences have been observed between coastal and inland stations. The majority of the coastal stations have shown a high increase in MMaxT as compared to the inland and hill stations. On the contrary, the inland stations have shown a high increase in MMinT as compared to the coastal stations. A more definite increasing trend is observed during the winter and postmonsoon seasons followed by the monsoon season.

Recovery, statistical validation and analysis of a historical meteorological dataset collected at the Hanbury Botanical Gardens (Liguria, northwestern Italy) from 1900 to 1940

A historical set of daily meteorological data collected at the Hanbury Botanical Gardens (Liguria, northwestern Italy) from 1900 to 1940 was recovered from five manually entered registers. They were digitised and statistically analysed to check their reliability and study their trends and variations. In particular, air temperature, precipitation and their extreme values were considered, together with wind direction, sea state, sky conditions and relative humidity. The results show a decreasing trend in mean annual temperature of approximately 0.2 °C/decade due to a decrease in maximum air temperature. Annual cumulative precipitation increased by 65.2 mm/decade over the study period. The data analysis showed a summer temperature decrease in 1912 and a severe drought in 1921. Moreover, the years with most days with extreme temperatures were associated to the negative phases of the North Atlantic oscillation (NAO). During the study period, SW winds were prevailing. Sky conditions followed seasonal trends, while slight sea was the most frequent sea state.

Change features and regional distribution of temperature trend and variability joint mode in mainland China

Adaption for temperature should be suitable to local conditions for regional differences in temperature change features. This paper proposed to utilize nine temperature modes that joint the trend (increasing/decreasing/unchanged) with variability (intensifying/weakening/unchanged) to investigate features of temperature change in mainland China. Monthly temperature data over the period 1960–2013 were obtained from 522 national basic and reference meteorological stations. Here, temperature trend (TT) was reflected by the trend of mean annual temperature (MAT) and the uptrend (downtrend) of inter-monthly sliding standard deviation (SSD) series with a sliding length of 29 years (348 months) was used for representing the intensification (weakening) of temperature variability (TV). The Mann-Kendall method and the least squares method were applied to assess the significance and quantify the magnitude of trend in MAT and SSD time series, respectively. The results show that there is a consistent warming trend throughout the country except for only three stations in which a cooling trend is identified. Moreover, the overall increasing rate in the north of 35° N is the highest, over 0.4 °C/decade for most stations. TV is weakened for almost 98% of the stations, indicating the low instability of temperature at a national scale. Finally, temperature mode (TM), for more than 90% of the stations, is the combination of an increasing TT with a weakened TV (mode 8). So, it is more important for people to adapt to the increasing temperature in these regions. Compared to using annual temperature data to calculate SSD, monthly data can accurately reflect the inter-monthly change of temperature and reserve more initial characteristics of temperature.

Spatiotemporal changes of geomorphic environment in the Muriganga–Saptamukhi estuarine interfluve of Indian Sundarban in the context of climate change: a case study

The surface of the earth has been continuously sculptured by the exogenetic processes primarily by the climatic hydrological attributes. Over the sequential phases of evolution of earth, the climatic attributes have altered. The alternative processes such as glaciation and declaciation, fluctuations of sea level and variability in rainfall pattern have changed the surface configuration through maneuvering the operations of the geographical processes. The issue of climate change has become a matter of scientific concern all over the world as the human communities are facing severe problems manifested in the form of flood, drought and submergence of low-lying coastal regions, estuaries and deltas. The present study is an attempt to understand the nature and extent of climate change (1890–2012) and related sea level rise (1970s–2010) in the deltaic Sundarban region of India since the last century and how far they are impacting the erosion–depositional processes (1925, 1926–2014). The changing trend of mean annual temperature, rainfall pattern and frequencies of tropical cyclones has been studied in detail, and spatiotemporal changes of geomorphic environment in different reaches of the study area have also been monitored with available multi-temporal geospatial data. The observation reveals that the flat sandy coastal belt and low-lying island in the extreme southern part have been severely affected by wave dash and seasonal storm surges which are mostly responsible for vigorous erosion. On the other hand, high tidal velocity is observed along the exposed concave bank in the upper–middle reaches of the Muriganga estuary and exposed outer bank in lower–middle reaches of Saptamukhi estuary. The thalweg line, which is very close to the river bank in those reaches of estuary, intensifies the hydraulic pressure along marginal parts of river bank which leads to erosion. Depositional activities are mostly observed along the sheltered inner reaches and convex river banks of the estuaries due to less effective tidal rushes, shallow channel depth, marginal flow velocity and gentle channel slope. Therefore, erosional and depositional processes cannot be explain by the relative mean sea level rise, because increasing mean sea level will affect the erosional processes uniformly in the entire estuary. In this present study area, both the erosional and depositional processes are simultaneously active depending on geographical exposure, sinuous channel pattern, channel depth and lithological compositions.

Analysis of VIA and EbA in a River Bank Erosion Prone Area of Bangladesh Applying DPSIR Framework

This study aims to set up a comprehensive approach to the Vulnerability and Impact Assessment (VIA) of river erosion and to suggest Ecosystem-based Adaptation (EbA) practices. Based on the analysis of vulnerability using the Driver-Pressure-State-Impact-Response (DPSIR) framework, this paper discusses some of the significant climatic (rainfall pattern, temperature, seasonal drift, cold wave and heat wave) and non-climatic (river erosion, repetitive death of field crops and agrochemicals) forces in the Kazipur Upazila (Sirajganj District)—a river erosion-prone area of Bangladesh. Both primary (Key Informants Interview, Household Survey, and Focus Group Discussion) and secondary (climatic, literature review) data have been used in revealing the scenario of climatic stress. The analysis revealed a slightly increasing trend of mean annual temperature, and a decreasing trend of total annual rainfall from 1981 to 2015, which have been supported by people’s perception. This study found that river erosion, the increase of temperature and the late arrival of monsoon rain, excessive monsoon rainfall, high use of agrochemicals, and flow alterations are major drivers in the riverine ecosystem. These drivers are creating pressures on agricultural land, soil fertility, water availability and livelihood patterns of affected communities. Hence, floating bed cultivation, integrated pest management, use of cover crops, reforestation, the introduction of an agro-weather forecasting system, and a new variety of flood tolerant species have been suggested as potential EbA to cope with river bank erosion and to increase the capacity of the affected ecosystem.

A Study of Maximum and Minimum Temperatures Trends at Junagadh (Saurashtra Region) of Gujarat, India

This paper, therefore, attempts to study temporal variation in temperature over Junagadh (Saurashtra Region) of Gujarat, India, India, during the period 1980-2011. The long-term change in temperature has been evaluated by Mann–Kendall rank statistics and linear trend. An important aspect of the present study is the significant cooling trend in mean annual temperature, which is more predominant during winter season. The summer season also shows significant cooling trend due to slightly decrease in Tmax. This cooling trend in Junagadh (Saurashtra Region) Gujarat, India temperature is supported by studies conducted by other researchers (Rupa Kumar and Hingane, 1988). These authors studied the temperature for Junagadh (Saurashtra region) Gujarat, India during the period 1980-2007 and observed a cooling trend, but not significant at any level. Against this background, in the present study, temperature data during the period 1980-2011 have been studied. The result indicates significant slightly decrease in winter temperature at 0.01 level. This suggests that the last decade has witnessed a phenomenal epoch in temperature series, leading to a decreasing trend from non-significant to significant. Contrary to this, the monsoon season shows warming trend. This may be due to significant increase in the low cloud amount during this season. We are still a long way from understanding the complex interaction of many physical processes that determine the evolution of climate.

Comparison of impacts of human activities and climate change on water quantity and quality in Finnish agricultural catchments

ContextWe studied the influence of human activities and climate change on water quantity and quality. Human activities included methods of agricultural policy, i.e. land use and management practices.ObjectivesFinland started to follow EU’s agricultural policy in 1995. In this study our main objective was to find out whether the original targets of the Finnish Agri-Environmental Programme (FAEP) were achieved.MethodsWe analyzed trends in discharge, water quality and climate parameters in 37 years long time-series in two catchments. We focused on the suspended sediment and phosphorus concentrations and loads, the main interests to FAEP.ResultsWe found an increasing trend in mean annual temperature, especially in spring and late summer-early autumn. There was no statistical significant change in annual runoff. Increasing winter runoff in the other catchment could be explained by the increased number of days when temperature was above zero degrees making snowmelt possible. In this area high potential sediment delivery occurred in early winter. FAEP succeeded in decreasing the suspended sediment load by reduced tillage and wintertime vegetation cover. In controlling the phosphorus loads FAEP succeeded only in the catchment with erosion sensitive soils. In the catchment where soils were less sensitive for erosion increase in the dissolved reactive phosphorus load exceeded the benefits of the reduced particulate phosphorus load.ConclusionsClimate change may increase the suspended sediment load by increasing winter runoff. Even then, instead of decreasing the suspended sediment loads FAEP should rather focus on dissolved nutrients as they cause eutrophication in receiving waters.

Observed and simulated changes in the water balance components over Malawi, during 1971–2000

Estimation of the spatial and temporal characteristics of key water balance components in data scarce regions is a large challenge worldwide. This paper presents the derivation of the 30-year surface water balance components (rainfall, temperature, potential and actual evapotranspiration (ETp and ETa) runoff). Monthly rainfall and mean temperature from 28 synoptic stations in Malawi during 1971–2000, together with soil moisture capacity extracted from the International Geosphere-Biosphere Programme Data Information Services (IGBP-DIS) Global Gridded Surfaces of Selected Soil Characteristics database at 0.5° × 0.5° grid resolution were used as model input. Ordinary Kriging was applied to examine the spatial distribution of the components using a 0.5° × 0.5° grid resolution. Temporal trends were investigated using the Mann–Kendall test at α = 0.05 significance level. The results showed: (1) an area of high rainfall, ETa and runoff areas located in the south east and north east highlands and decreasing westwards. Temperature and ETp were highest in the lower Shire River valley and along Lake Malawi; (2) Mann–Kendall trends suggested statistically significant positive trends in mean annual temperature and ETp and declines in annual rainfall, ETa and runoff, though their trends were not statistically significant. The contrasting trends ETp and ETa are a manifestation of the complementary relationship. The decline in rainfall coupled with temperature increase suggests that Malawi became more water-limited during 1971–2000.

Variability and trend in the hydrology of the Yangtze River, China: Annual precipitation and runoff

Summary The catchment of the Yangtze River in China has a long history of human occupation and the intensity of human impacts has increased markedly since economic reforms began in the late 1970s. In order to try to assess the impact of these changes on the hydrology of the river, we analyse both the annual flows of the Yangtze River and annual temperature and precipitation for the Yangtze catchment for the period 1955–2011 and for the three sections of the catchment, Upper, Middle and Lower as defined by the location of the gauging stations at Yichang, Hankou and Datong respectively. Mean annual temperature increases downstream from 12.7 °C in the Upper to 16.0 °C in the Lower section. A significant increasing trend in mean annual temperature is detected over the period 1955–2011 in the whole catchment and all subsections. Mean annual precipitation for the whole catchment is 1045 mm ranging from 859 mm in the elevated Upper section to 1528 mm in the Lower section. Precipitation variability is low by world standards with an annual Cv of 0.066. Using the Mann–Kendal and Rank Sums tests we do not find any trend in precipitation in the catchment. Mean annual runoff for the whole catchment is 515 mm ranging from 421 mm in the Upper Catchment to 838 mm in the Lower Catchment. Runoff variability is also low by world standards with an annual runoff Cv of 0.129. For the Middle Catchment we find a small but statistically significant increase in runoff and the runoff ratio over the period 1955–2011, possibly caused by change in the nature of the surface due to accelerated urbanization post 1980 and increased area of water storage. Overall, annual runoff in the Yangtze River shows little response to the major changes occurring in the basin. In a multiple correlation analysis of discharge, precipitation, dam volume, population and GDP, only precipitation is significantly correlated with discharge, explaining 80% of the variance. Widespread reporting of the impact of development on the annual water yield of the Yangtze, especially the impact of dams and notably the Three Gorges Dam, are not supported by this analysis.

Influence of Climate Change on Soil Water Regime in Koprivnica-Križevci County

AbstractSpoljar A., Kisic I., Peremin Volf, T., Kamenjak D., Kaucic D.: Influence of climate change on soil water regime in Koprivnica-Krizevci County. Ekológia (Bratislava), Vol. 33, No. 2, p. 178-187, 2014.The influence of climate change on soil water regime was investigated in the area of Koprivnica- -Krizevci County (Republic of Croatia). Water balance calculations were done for three climatic stations using Thornthwaite and Palmer water balance methods. In the 18-year period (from 1991 to 2008), compared with the previously observed 30-year period (from 1961 to 1990), the increase in average mean annual temperature was 1°C. Regarding the global warming, there was an increase in plant water potential during the investigated period. Compared with the previous period and according to Thornthwaite and Palmer methods, there was an increase in water deficit. Negative linear trend in precipitation was detected for all climate stations in the investigated area (p > 0.05) as well as positive linear trend in mean annual temperature (p < 0.05). The calculation of linear trend in water deficit in soil, according to Thornthwaite method, shows that by the year 2020 there could be an increase in water deficit by an average of 13 mm (p > 0.05), whereas according to the Palmer method there could be an increase by an average of 9 mm (p < 0.05 only for the climate station in Krizevci).

Vulnerability of artisanal fisheries to climate change in the Venice Lagoona

Within the context of global warming, the western coast of the northern Adriatic Sea can be regarded as an extremely vulnerable area. Owing to the local geographic features, this area has been described as the Venetian lacuna, where Mediterranean Sea climatic conditions are replaced by Atlantic Ocean ones, supporting the presence of glacial relicts, such as sprat Sprattus sprattus, flounder Platichthys flesus and brown shrimp Crangon crangon. Nektonic assemblage therefore represents a good candidate in terms of an early proxy for thermal regime alterations. It represents a dynamic component of the lagoon ecosystem, changing in space and time, actively moving through the entire system, and dynamically exchanging with the open sea. Here, the first signals of the change have been already detected, such as the presence of alien thermophilic species. Within this context, since the beginning of the century, sampling of the nektonic assemblage has been carried out, integrating them with landings data from the fish market. Vulnerabilities to thermal regime changes have been tested by (1) categorizing species according to the mean distribution area in terms of latitudinal range (over 45°, 30°-45° and below 30°), and (2) analysing both spatial and temporal variations within fishing grounds. Results indicated a high potential vulnerability of the artisanal fishery to climate change, as the commercial catch is entirely composed of species from cold (>45° N) and temperate (between 45° and 30° N) latitudes. At present no alien thermophilic species have been recorded within the lagoon, which is possibly a sign of good resilience of the assemblage. Finally, abundance of species from cold latitudes has decreased during the past decade. All of this has been discussed in the context of the mean annual temperature trend.

Recent palaeolimnological change recorded in Lake Xiaolongwan, northeast China: Climatic versus anthropogenic forcing

Lake Xiaolongwan is a closed maar lake located in the Long Gang Volcanic Field, northeast China. Core XLW2 was collected in 2007 from the central region of the lake and provides a palaeoecological reconstruction over the past ca. 130 years (dated using radiometric methods: 210Pb and 137Cs). Diatom floristic changes and catchment productivity (carbon isotope ratios) were analysed within the core. Indicators of atmospheric pollution (XRF and SCP inventories) were also measured. Results show a marked transition from a dominant benthic assemblage to a planktonic one (increasing P:B ratios) starting after ca. 1940 AD, becoming most prominent after ca. 1980 AD (P:B > 1). Most notable floristic changes result from the increase in the planktonic species Discostella woltereckii. These changes are concomitant with increased temperature trends from the region and reconstructed temperature anomalies of the Northern Hemisphere. SCP concentrations and flux rates also increase after ca. 1950 AD, with highest values seen at ca. 1980 AD after which values decline. Normalised elemental geochemistry (e.g. Pb/Ti) also show marked changes after ca. 1970 AD, most likely derived from atmospheric deposition of Pb. The recent increase in D. woltereckii precedes anthropogenic contamination (Pb/Ti) at the site and persists after the decline in SCP concentrations. This suggests that the recent increases are driven by increased mean annual temperature trends. These temperature trends may be manifested as changes in ice cover persistence, a longer growing season and/or increased DOC at Lake Xiaolongwan: conditions for which planktonic species have a more competitive advantage.