Precipitation Temperature Changes Research Articles

Ensemble projections of climate and streamflow in a typical basin of semi-arid steppes in Mongolian Plateau of 2021–2100

The Kherlen River is the main water source for Hulun Lake, the largest lake in northern China. Due to reduced inflow from the Kherlen River, Hulun Lake experienced rapid shrinkage at the beginning of the 21st century, posing a serious threat to the ecological security of northern China. However, there is still a significant lack of projections regarding future climate change and its hydrological response in the Kherlen River basin. This study analyzed the projected climate and streamflow changes in the Kherlen River basin, a vital yet vulnerable international semi-arid steppes type basin. A combination of multi-model ensemble projection techniques, and the soil and water assessment tool (SWAT) model was employed to examine the spatio‒temporal changes in precipitation, temperature, streamflow, and the associated uncertainties in the basin. The temperature (an increase of 1.84–6.42 °C) and the precipitation (an increase of 15.0–46.0 mm) of Kherlen River basin are projected to increase by 2100, leading to a rise in streamflow (1.08–4.78 m3 s−1). The upstream of the Kherlen River exhibits remarkable increasing trends in precipitation, which has a dominant influence on streamflow of Kherlen River. Noteworthy increases in streamflow are observed in April, August, September, and October compared to the reference period (1971–2000). These findings suggest a partial alleviation of water scarcity in the Kherlen River, but also an increased likelihood of hydrological extreme events. The projected temperature increase in the Kherlen River basin exhibits the smallest uncertainty, while more pronounced uncertainties are found in precipitation and streamflow. The spread among the results of CMIP6 models is greater than that of CMIP5 models, with lower signal-to-noise ratio (SNR) values for temperature, precipitation, and streamflow.

Evaluating future changes in the South Indian Ocean Convergence Zone projected by CMIP5 models and associated uncertainty

Southern Africa relies heavily on precipitation for agricultural purposes; therefore, spatial and temporal changes in precipitation are crucial to identify and understand. The South Indian Ocean Convergence Zone (SIOCZ), a large-scale, austral summer rainfall feature extending across southern Africa into the southwest Indian Ocean, is evaluated in future projections. Using a best-fit algorithm, future projections of the SIOCZ are determined, which indicate a northward shift of approximately 120 km in CMIP5 models under RCP8.5. A dipole pattern of precipitation wetting/drying is evident, where wetting occurs to the north of the climatological axis of maximum rainfall, implying a northward shift of the Inter Tropical Convergence Zone, consistent with the SIOCZ shift. Common drivers responsible for model changes include enhanced warming in the northern Indian Ocean in line with the ‘warmest-get-wetter’ sea surface temperature hypothesis, which impacts circulation by transporting moisture away from the SIOCZ towards the equator. Most CMIP5 models exhibit drying trends over the SIOCZ region, with mechanisms driving uncertainty related to diverse warming trends across models. Empirical orthogonal function patterns of future precipitation changes across CMIP5 models exhibit a pattern much like the SIOCZ, which is related to inter-model changes in future temperature changes. Reductions in model spread are established in SIOCZ projections, whereby model processes of change exhibit agreement, despite differing initial SIOCZ conditions. Therefore, model process convergence and coherence are established with respect to projected changes in the SIOCZ, irrespective of initial climatology biases. Understanding future changes in this feature will help inform decision-making for water and agriculture adaptation planning in southern Africa.

Variation in the hydrological cycle in the Three-River Headwaters Region based on multi-source data

The hydrological processes in the Three-River Headwaters Region (TRHR), which is located in the Qinghai-Tibetan Plateau and includes the Yangtze River Headwater Region (YARHR), the Yellow River Headwater Region (YERHR), and the Lantsang River Headwater Region (LARHR), have changed under climate warming. Based on multi-source data, the spatial and temporal changes in precipitation, evapotranspiration, soil water storage, glacier melt, snowmelt and runoff in the Three-River Headwaters Region from 1982 to 2014 were comprehensively analysed. The annual precipitation data for the Three-River Headwaters Region from ERA5-Land, the Climatic Research Unit, the China Meteorological Forcing Dataset and the Global Land Data Assimilation System (GLDAS) all showed an increasing trend; the annual evapotranspiration data from ERA5-Land, Global Land Data Assimilation System, Global Land Evaporation Amsterdam Model (GLEAM) and Terrestrial Evapotranspiration Dataset across China (TEDC) all showed an increasing trend; and the annual soil water storage data from ERA5-Land, Global Land Data Assimilation System and Global Land Evaporation Amsterdam Model all showed an increasing trend. The annual snowmelt data from ERA5-Land, Global Land Data Assimilation System and SMT-Y datasets all showed a decreasing trend. The annual glacier melt increased in the Yangtze River Headwater Region and Yellow River Headwater Region and decreased in the Lantsang River Headwater Region. The increases in precipitation, evapotranspiration, soil water content and glacial melt, and the decreases in snowfall and snowmelt indicate an accelerated hydrological cycle in the Three-River Headwaters Region over the 1982 to 2014 period. The significant increase in precipitation is the main reason for the significant increase in runoff in the Yangtze River Headwater Region. The increase in precipitation in the Yellow River Headwater Region was less than the sum of the increase in evapotranspiration and soil water storage, resulting in a decreasing trend of runoff in the Yellow River Headwater Region. The increase in precipitation in the Lantsang River Headwater Region was slightly larger than the sum of that in evapotranspiration and soil water storage, and there was an insignificant increase in the runoff in the Lantsang River Headwater Region.

Precipitation effects on nematode diversity and carbon footprint across grasslands.

Free-living nematodes are one of the most diverse metazoan taxa in terrestrial ecosystems and are critical to the global soil carbon (C) cycling through their role in organic matter decomposition. They are highly dependent on water availability for movement, feeding, and reproduction. Projected changes in precipitation across temporal and spatial scales will affect free-living nematodes and their contribution to C cycling with unforeseen consequences. We experimentally reduced and increased growing season precipitation for 2years in 120 field plots at arid, semiarid, and mesic grasslands and assessed precipitation controls on nematode genus diversity, community structure, and C footprint. Increasing annual precipitation reduced nematode diversity and evenness over time at all sites, but the mechanism behind these temporal responses differed for dry and moist grasslands. In arid and semiarid sites, there was a loss of drought-adapted rare taxa with increasing precipitation, whereas in mesic conditions increases in the population of predaceous taxa with increasing precipitation may have caused the observed reductions in dominant colonizer taxa and yielded the negative precipitation-diversity relationship. The effects of temporal changes in precipitation on all aspects of the nematode C footprint (respiration, production, and biomass C) were all dependent on the site (significant spatial×temporal precipitation interaction) and consistent with diversity responses at mesic, but not at arid and semiarid, grasslands. These results suggest that free-living nematode biodiversity and their C footprint will respond to climate change-driven shifts in water availability and that more frequent extreme wet years may accelerate decomposition and C turnover in semiarid and arid grasslands.

The June 2020 Aniangzhai landslide in Sichuan Province, Southwest China: slope instability analysis from radar and optical satellite remote sensing data

A large, deep-seated ancient landslide was partially reactivated on 17 June 2020 close to the Aniangzhai village of Danba County in Sichuan Province of Southwest China. It was initiated by undercutting of the toe of this landslide resulting from increased discharge of the Xiaojinchuan River caused by the failure of a landslide dam, which had been created by the debris flow originating from the Meilong valley. As a result, 12 townships in the downstream area were endangered leading to the evacuation of more than 20000 people. This study investigated the Aniangzhai landslide area by optical and radar satellite remote sensing techniques. A horizontal displacement map produced using cross-correlation of high-resolution optical images from Planet shows a maximum horizontal motion of approximately 15 meters for the slope failure between the two acquisitions. The undercutting effects on the toe of the landslide are clearly revealed by exploiting optical data and field surveys, indicating the direct influence of the overflow from the landslide dam and water release from a nearby hydropower station on the toe erosion. Pre-disaster instability analysis using a stack of SAR data from Sentinel-1 between 2014 and 2020 suggests that the Aniangzhai landslide has long been active before the failure, with the largest annual LOS deformation rate more than 50 mm/yr. The 3-year wet period that followed a relative drought year in 2016 resulted in a 14% higher average velocity in 2018–2020, in comparison to the rate in 2014–2017. A detailed analysis of slope surface kinematics in different parts of the landslide indicates that temporal changes in precipitation are mainly correlated with kinematics of motion at the head part of the failure body, where an accelerated creep is observed since spring 2020 before the large failure. Overall, this study provides an example of how full exploitation of optical and radar satellite remote sensing data can be used for a comprehensive analysis of destabilization and reactivation of an ancient landslide in response to a complex cascading event chain in the transition zone between the Qinghai-Tibetan Plateau and the Sichuan Basin.

Spatiotemporal and cross-scale interactions in hydroclimate variability: a case-study in France

Abstract. Understanding how water resources vary in response to climate at different temporal and spatial scales is crucial to inform long-term management. Climate change impacts and induced trends may indeed be substantially modulated by low-frequency (multi-year) variations, whose strength varies in time and space, with large consequences for risk forecasting systems. In this study, we present a spatial classification of precipitation, temperature, and discharge variability in France, based on a fuzzy clustering and wavelet spectra of 152 near-natural watersheds between 1958 and 2008. We also explore phase–phase and phase–amplitude causal interactions between timescales of each homogeneous region. A total of three significant timescales of variability are found in precipitation, temperature, and discharge, i.e., 1, 2–4, and 5–8 years. The magnitude of these timescales of variability is, however, not constant over the different regions. For instance, southern regions are markedly different from other regions, with much lower (5–8 years) variability and much larger (2–4 years) variability. Several temporal changes in precipitation, temperature, and discharge variability are identified during the 1980s and 1990s. Notably, in the southern regions of France, we note a decrease in annual temperature variability in the mid 1990s. Investigating cross-scale interactions, our study reveals causal and bi-directional relationships between higher- and lower-frequency variability, which may feature interactions within the coupled land–ocean–atmosphere systems. Interestingly, however, even though time frequency patterns (occurrence and timing of timescales of variability) were similar between regions, cross-scale interactions are far much complex, differ between regions, and are not systematically transferred from climate (precipitation and temperature) to hydrological variability (discharge). Phase–amplitude interactions are indeed absent in discharge variability, although significant phase–amplitude interactions are found in precipitation and temperature. This suggests that watershed characteristics cancel the negative feedback systems found in precipitation and temperature. This study allows for a multi-timescale representation of hydroclimate variability in France and provides unique insight into the complex nonlinear dynamics of this variability and its predictability.

Rainfall seasonality effects on vegetation greenness in different ecological zones

This study assesses the spatial and temporal changes in precipitation and its effects on vegetation greenness over six ecological zones in Nigeria. Both vegetation and climatological satellite datasets were used for this study. Satellite climatological data include African Rainfall Estimation Algorithm (RFE) and Climate Hazards Group Infrared Precipitation with their respective Stations (CHIRPS), while Moderate Resolution Imaging Spectroradiometer (MODIS) was used to examine variations in vegetation greenness over time. Both rainfall variability estimation and the normalized difference vegetation index (NDVI) analysis were carried out. The results show that there is a significant spatiotemporal variation in precipitation in the different ecological zones. It is obvious that precipitation influences vegetation greenness in all ecological zones, but much more in Sahel and Sudan ecological zones. The results from correlation reveal a significant relationship between NDVI and CHIRPS with R2 > 0.50, especially in the Sahel, Sudan, and Guinea savannah ecological zones. The relationship between RFE and NDVI further revealed a slightly moderate degree of relationship with 0.40 < R2 > 0.49. This study demonstrates that precipitation has a significant influence on vegetation productivity and greenness. The study concludes on the note that rainfall seasonality determines variations in vegetation greenness to a significant extent in all the ecological zones.

The increasing water clarity of Tibetan lakes over last 20 years according to MODIS data

Water clarity is a comprehensive indicator of the water environment status. Studies have shown that in recent years the clarity of inland and ocean water has decreased in many parts of the world owing to the influence of climate change and human activities. However, changes in inland water clarity exclusively resulting from climate change are largely ignored because most inland water is being utilized by human beings for applications such as waterworks or aquaculture. Therefore, understanding the trends and reasons of inland water clarity under natural conditions is important to recognize the inland water environment shifts under the global changes. Because of the harsh environment, the lakes on the Tibetan Plateau are less disturbed by human activities and are ideal objects for studying water clarity variations attributed to climatic changes. Here, we describe water clarity changes as measured using the Secchi Depth (SD) in 152 big lakes with an area greater than 50 km2 based on in-situ investigations and the retrieval results from a high accuracy retrieval model (r = 0.94, P < 0.01). Most of the lakes had an SD of 3–10 m, although there was marked spatial variation and a significant positive correlation with lake area (P < 0.01). The mean SD of all 152 lakes significantly increased at a rate of 0.033 m/year (95% CI, 0.021–0.045; P < 0.01) between 2000 and 2019. Variations in lake SD were linked with temporal changes in precipitation, and related to spatial changes of water optical components including suspended matter (0.13 < R2 < 0.40, P < 0.01 or P < 0.05), fDOM (R2 = 0.24, P < 0.01) and chlorophyll-a concentration (R2 = 0.12, P < 0.01).The reconstructed lake water clarity in our study will improve the understanding of inland water clarity changes and provide basic data to study the heat exchanges between lake water and atmosphere.

Soil microbial biomass and community responses to experimental precipitation change: A meta-analysis

The activity of soil microbes is strongly constrained by water availability. However, it is unclear how microbial activity responds to spatial and temporal changes in precipitation, particularly to long-term precipitation changes. To identify the spatiotemporal patterns of microbial responses to precipitation changes of differing durations, we conducted a meta-analysis of data from 95 field studies with drought treatments and 109 field studies with elevated precipitation treatments. Our results indicated that microbial biomass carbon (MBC) decreased by 17% under drought and increased by 18% under elevated precipitation. Across all studies, the phospholipid fatty acid (PLFA) biomarkers for fungi and bacteria decreased significantly under drought but increased under elevated precipitation. In addition, the negative effect of drought on MBC tended to be greater at sites with a high aridity index, but the effect of elevated precipitation on MBC did not differ among sites. More importantly, the responses of MBC, fungal and bacterial PLFA abundance did not vary with treatment duration under drought, but under elevated precipitation, they increased in the first five years of treatment and declined thereafter. These results are important for our prediction of microbial responses to long-term precipitation change, because they imply that microbes acclimate to long-term elevated precipitation.

Current Evidence and Future Projections: a Comparative Analysis of the Impacts of Climate Change on Critical Climate-Sensitive Areas of Papua New Guinea

Climate change is a global concern arising from spatial or temporal changes in precipitation, temperature and greenhouse gases. The impacts of this on critical climate-sensitive areas are largely on land, marine resources, forestry and agriculture, and their biodiversity and ecosystems. In Papua New Guinea (PNG), the mainstay (85%) of the rural people is on land and agriculture, compared to resources obtained from the marine areas and forest. Productivity on land depends on climatic factors and a compromised climate affects land, which in turn affects forestry, agriculture and the marine environment (resources and ecosystems). Because of this, a lot of resources have been invested in climate change to understand the impacts; however, much is yet to be achieved, especially in the developing nations. In PNG, understanding the types of changes in climate that will be experienced is important to be resilient, to mitigate and to adapt. In this review, the potential impact of global climate change on climate of PNG and the impact of the new (future) climate on land, marine and forest resources and their biodiversity and ecosystems are analyzed. Moreover, the impacts on crop agriculture are discussed. Analysis of available data shows that the temporal and spatial changes in precipitation and temperature projections of the future climate are within current optimum crop production ranges, at least up to 2090. Since most staple and plantation crops in PNG are C&lt;sub&gt;3&lt;/sub&gt; plants, an increase in CO&lt;sub&gt;2&lt;/sub&gt; levels will have a fertilizing effect on productivity. The plastic effects on certain crops may benefit some farmers as temperature, precipitation and CO&lt;sub&gt;2&lt;/sub&gt; levels change.

Body size structure of soil fauna along geographic and temporal gradients of precipitation in grasslands

Precipitation is a global driver of animal abundance and diversity in terrestrial ecosystems, but we know little on how it influences the body size structure of invertebrate communities, particularly soil fauna. It is unclear whether aridity limits the abundance of large-bodied soil invertebrates, and whether temporal precipitation changes can induce local shifts. The potential role of trophic identity in modulating such relationships is also unexplored. Here we investigate the community-weighted mean body mass of soil nematodes, globally widespread invertebrates, in a two-year manipulative experiment with experimental drought and increased rainfall, conducted in three North American grassland ecosystems ranging from arid to semiarid and mesic conditions. We predict that community-weighted mean increases along with precipitation, and that long-term aridity prevents body size shifts in response to within-site temporal changes in precipitation. Nematode community-weighted mean mass increased from arid to mesic conditions. Altered precipitation within sites had much weaker effects, and none detectable in the arid site. When analysing community-weighted mean mass separately by feeding group, only plant-feeding nematodes responded positively to rainfall addition in semiarid and mesic conditions, as well as to ambient interannual differences consistently across sites, presumably due to a tighter ecological linkage with primary production. Our findings point to aridity as an environmental filter against large-bodied soil nematodes, with limited potential for community body size shifts in response to extremely dry or wet years. However, the different responses of plant-feeding taxa from other functional groups indicate potential mismatches between morphologically similar taxa in multitrophic invertebrate communities.

Nitrogen deposition magnifies the sensitivity of desert steppe plant communities to large changes in precipitation

Abstract Precipitation alteration and nitrogen (N) deposition caused by anthropogenic activities could profoundly affect the structure and functioning of plant communities in arid ecosystems. However, the plant community impacts conferred by large temporal changes in precipitation, especially with a concurrent increase in N deposition, remain unclear. To address this uncertainty, from 2016 to 2017, an in situ field experiment was conducted to examine the effects of five precipitation levels, two N levels and their interaction on the plant community function and composition in a desert steppe in northern China. Above‐ground net primary production (ANPP) and plant community‐weighted mean (CWM) height significantly increased with increasing precipitation, and both were well fitted with a positive linear model, but with a higher slope under N addition. The ANPP increase was primarily driven by the increase in Artemisia capillaris, a companion forb sensitive to precipitation variation. The plant community composition shifted with precipitation enhancement—from a community dominated by Stipa tianschanica, a perennial grass, to a community dominated by Artemisia capillaris. Synthesis. The findings imply that the ecosystem sensitivity to future changes in precipitation variability will be mediated by two potential mechanisms: concurrent N deposition and plant community‐level change. It is suggested that we should consider the vegetation compositional shift and multiple resource colimitation in assessing the sensitivity of terrestrial ecosystems to climate change.

Review on Effect of Climate Change and Urbanization on Agriculture

Climate is the primary important factor for agricultural production. The work topics concentrate possible physical effects of climatic change on agriculture, such as changes in crop and livestock yields as well as the economic consequences of these potential yield changes. In addition to this understanding of long-term changes in precipitation and temperature patterns is important in the detection and characterization of climate change. The role that climatic change has played in the pattern of urbanization in sub-Saharan African countries compared to the rest of the developing world and climatic changes represented by rainfall, has acted to change urbanization in sub-Saharan Africa. The cultivated land loss due to urbanization not only threatens food security in, but has also led to ecological system degradation to which close attention should be paid. In other hand climate change and urbanization have caused temporal changes in precipitation and temperature. Finally this paper reviews the effects of climate change and urbanization on agriculture. The main interests, concerning the role of human adaptations in responding to climate change, the impacts of climate change and urbanization, possible regional impacts to agricultural systems and potential changes in patterns of food production. Keywords: Agriculture, climate change, global warming, impact, urbanization DOI : 10.7176/CER/11-5-04 Publication date :June 30 th 2019

Temporal Changes in Precipitation and Temperature and their Implications on the Streamflow of Rosi River, Central Nepal

Nepal has experienced recent changes in two crucial climatic variables: temperature and precipitation. Therefore, climate-induced water security concerns have now become more pronounced in Nepal as changes in temperature and precipitation have already altered some hydrological processes such as the river runoff in some river systems. However, the linkage between precipitation patterns and streamflow characteristics are poorly understood, especially in small rivers. We analysed the temporal trends of temperature, precipitation, and extreme indices of wet and dry spells in the Rosi watershed in Central Nepal, and observed the temporal patterns of the streamflow of the Rosi river. We also examined the linkages between the average and extreme climate indices and streamflow. We found that the area has warmed up by an average of 0.03 °C/year, and has seen a significant decline in precipitation. The dry spell as represented by the maximum length of the dry spell (CDD) and the magnitude of dryness (AII) has become more pronounced, while the wet spell as represented by the number of heavy rainfall days (R5D) and the precipitation intensity on wet days (SDII) has diminished significantly. Our analysis shows that recent changes in precipitation patterns have affected the streamflow of the Rosi river, as manifested in the observed decline in annual and seasonal streamflows. The decrease in the availability of water in the river is likely to have severe consequences for water security in the area.

The Fingerprint of Climate Change and Urbanization in South Korea

Understanding long-term changes in precipitation and temperature patterns is important in the detection and characterization of climate change, as is understanding the implications of climate change when performing impact assessments. This study uses a statistically robust methodology to quantify long-, medium- and short-term changes for evaluating the degree to which climate change and urbanization have caused temporal changes in precipitation and temperature in South Korea. We sought to identify a fingerprint of changes in precipitation and temperature based on statistically significant differences at multiple-timescales. This study evaluates historical weather data during a 40-year period (1973–2012) and from 54 weather stations. Our results demonstrate that between 1993–2012, minimum and maximum temperature trends in the vicinity of urban and agricultural areas are significantly different from the two previous decades (1973–1992). The results for precipitation amounts show significant differences in urban areas. These results indicate that the climate in urbanized areas has been affected by both the heat island effect and global warming-caused climate change. The increase in the number of rainfall events in agricultural areas is highly significant, although the temporal trends for precipitation amounts showed no significant differences. Overall, the impacts of climate change and urbanization in South Korea have not been continuous over time and have been expressed locally and regionally in terms of precipitation and temperature changes.

A Global Assessment of Runoff Sensitivity to Changes in Precipitation, Potential Evaporation, and Other Factors

AbstractPrecipitation (P) and potential evaporation (Ep) are commonly studied drivers of changing freshwater availability, as aridity (Ep/P) explains ∼90% of the spatial differences in mean runoff across the globe. However, it is unclear if changes in aridity over time are also the most important cause for temporal changes in mean runoff and how this degree of importance varies regionally. We show that previous global assessments that address these questions do not properly account for changes due to precipitation, and thereby strongly underestimate the effects of precipitation on runoff. To resolve this shortcoming, we provide an improved Budyko‐based global assessment of the relative and absolute sensitivity of precipitation, potential evaporation, and other factors to changes in mean‐annual runoff. The absolute elasticity of runoff to potential evaporation changes is always lower than the elasticity to precipitation changes. The global pattern indicates that for 83% of the land grid cells runoff is most sensitive to precipitation changes, while other factors dominate for the remaining 17%. This dominant role of precipitation contradicts previous global assessments, which considered the impacts of aridity changes as a ratio. We highlight that dryland regions generally display high absolute sensitivities of runoff to changes in precipitation, however within dryland regions the relative sensitivity of runoff to changes in other factors (e.g., changing climatic variability, CO2‐vegetation feedbacks, and anthropogenic modifications to the landscape) is often far higher. Nonetheless, at the global scale, surface water resources are most sensitive to temporal changes in precipitation.

Analysis of Potential Future Climate and Climate Extremes in the Brazos Headwaters Basin, Texas

Texas’ fast-growing economy and population, coupled with cycles of droughts due to climate change, are creating an insatiable demand for water and an increasing need to understand the potential impacts of future climates and climate extremes on the state’s water resources. The objective of this study was to determine potential future climates and climate extremes; and to assess spatial and temporal changes in precipitation (Prec), and minimum and maximum temperature (Tmin and Tmax, respectively), in the Brazos Headwaters Basin under three greenhouse gas emissions scenarios (A2, A1B, and B1) for three future periods: 2020s (2011–2030), 2055s (2046–2065), and 2090s (2080–2099). Daily gridded climate data obtained from Climate Forecast System Reanalysis (CFSR) were used to downscale outputs from 15 General Circulation Models (GCMs) using the Long Ashton Research Station–Weather Generator (LARS-WG) model. Results indicate that basin average Tmin and Tmax will increase; however, annual precipitation will decrease for all periods. Annual precipitation will decrease by up to 5.2% and 6.8% in the 2055s and 2090s, respectively. However, in some locations in the basin, up to a 14% decrease in precipitation is projected in the 2090s under the A2 (high) emissions scenario. Overall, the northwestern and southern part of the Brazos Headwaters Basin will experience greater decreases in precipitation. Moreover, precipitation indices of the number of wet days (prec ≥ 5 mm) and heavy precipitation days (prec ≥ 10 mm) are projected to slightly decrease for all future periods. On the other hand, Tmin and Tmax will increase by 2 and 3 °C on average in the 2055s and 2090s, respectively. Mostly, projected increases in Tmin and Tmax will be in the upper range in the southern and southeastern part of the basin. Temperature indices of frost (Tmin &lt; 0 °C) and ice days (Tmax &lt; 0 °C) are projected to decrease, while tropical nights (Tmin &gt; 20 °C) and summer days (Tmax &gt; 25 °C) are expected to increase. However, while the frequency distribution of metrological drought shows slight shifts towards the dry range, there was no significant difference between the baseline and projected metrological drought frequency and severity.

Late quaternary climate, precipitation δ18O, and Indian monsoon variations over the Tibetan Plateau

The Himalaya–Tibet orogen contains one of the largest modern topographic and climate gradients on Earth. Proxy data from the region provide a basis for understanding Tibetan Plateau paleo climate and paleo elevation reconstructions. Paleo climate model comparisons to proxy data compliment sparsely located data and can improve climate reconstructions. This study investigates temporal changes in precipitation, temperature and precipitation δO18(δOp18) over the Himalaya–Tibet from the Last Glacial Maximum (LGM) to present. We conduct a series of atmospheric General Circulation Model (GCM, ECHAM5-wiso) experiments at discrete time slices including a Pre-industrial (PI, Pre-1850 AD), Mid Holocene (MH, 6 ka BP) and LGM (21 ka BP) simulations. Model predictions are compared with existing proxy records. Model results show muted climate changes across the plateau during the MH and larger changes occurring during the LGM. During the LGM surface temperatures are ∼2.0–4.0°C lower across the Himalaya and Tibet, and >5.0 °C lower at the northwest and northeast edge of the Tibetan Plateau. LGM mean annual precipitation is 200–600 mm/yr lower over on the Tibetan Plateau. Model and proxy data comparison shows a good agreement for the LGM, but large differences for the MH. Large differences are also present between MH proxy studies near each other. The precipitation weighted annual mean δ18Op lapse rate at the Himalaya is about 0.4‰/km larger during the MH and 0.2‰/km smaller during the LGM than during the PI. Finally, rainfall associated with the continental Indian monsoon (between 70°E–110°E and 10°N–30°N) is about 44% less in the LGM than during PI times. The LGM monsoon period is about one month shorter than in PI times. Taken together, these results document significant spatial and temporal changes in temperature, precipitation, and δ18Op over the last ∼21 ka. These changes are large enough to impact interpretations of proxy data and the intensity of the Indian monsoon.

Recent precipitation trends, flash floods and landslides in southern Brazil

In order to understand the rising number of flash floods and landslides in the densely populated region of southeastern Brazil, this study analyzes the spatial and temporal changes in precipitation from 1978 to 2014. We focus on the sensitivity of mountainous regions, specifically the Rio de Janeiro (RJMR) and Santa Catarina (SCMR) regions. Daily rainfall observations are aggregated into annual and seasonal indexes, and RClimdex is used to evaluate a suite of precipitation and extreme event indexes. Results show positive annual and seasonal precipitation trends during all seasons except for the winter season in the RJMR. Diverse change points in their time series, spatial differences in the trends at individual stations, and trends associated with elevation suggest that despite the close proximity of these two regions, climate impacts are not uniform across all of southeastern Brazil. The majority of precipitation-related indexes present positive trends, especially in the extreme precipitation indexes (PRCPTOT, RX1day, Rx5day and R30 mm). Statistically significant positive correlations are discovered between landslides/flash floods events and annual maximum 1-day and 5-day consecutive precipitation, and these indexes may be useful indicators of natural hazard events for this region.

Desarrollo del sistema de información de la red de pluviómetros alternativos en medios rurales. Caso estado Anzoátegui, Venezuela

Knowledge of temporal changes in precipitation and its interaction with other components of the agricultural system facilitates agricultural planning, allowing better use of resources. The aim of this work was to develop an information system Network Alternative Pluviometers in rural areas of Anzoategui state. 22 Units of agricultural production plant located in different municipalities in the state were selected. Methodology of participatory action research and social intervention method was applied. Subsequently, network was integrated to the Information System of Agroecological Areas of the National Institute for Agricultural Research (INIA, by its Spanish acronym), providing opportunity to learn local characteristics of rain. The information system network aims to boost domestic development of communities where creation of new alternatives for use and management practices with ecological, economic and alternative approach makes possible, by strengthening capacity to innovate and disseminate technologies like based on planning in agriculture.