Number Of Precipitation Events Research Articles

Atmospheric conditions favouring extreme precipitation and flash floods in temperate regions of Europe

Abstract. In recent years, flash floods have repeatedly occurred in temperate regions of central western Europe. Unlike in Mediterranean catchments, this flooding behaviour is unusual. In the past (especially in the 1990s), floods have been characterized by predictable, slowly rising water levels during winter and driven by westerly atmospheric fluxes. Here, we explore potential links and causes between the recent occurrence of flash floods in central western Europe to extreme precipitation and specific atmospheric conditions. We hypothesize that a change in atmospheric conditions has led to more frequent extreme precipitation events that have subsequently triggered flash flood events in central western Europe. To test this hypothesis, we compiled data on flash floods in central western Europe and selected precipitation events above 40 mm h−1 from radar data (the RADOLAN “Radar-Online-Adjustment” dataset from the German Weather Service). Moreover, we identified proxy parameters representative of extreme precipitation favouring atmospheric conditions from the ERA5 reanalysis dataset. High specific humidity (q) in the lower troposphere (q≥0.004 kg kg−1), sufficient latent instability (convective available potential energy (CAPE) ≥ 327 J kg−1), and weak wind speeds between 10 m a.g.l. and 500 hPa (WS10m-500hPa≤6 m s−1) proved to be characteristic of intense rainfall that can potentially trigger flash floods. We relied on linear models to analyse 40 years worth (1981–2020) of atmospheric parameters as well as related precipitation events. We found significant increases in the atmospheric moisture content and increases in atmospheric instability. Parameters representing the motion and organization of convective systems remained largely unchanged in the considered period (1981–2020); however, the number of precipitation events, their maximum 5 min intensities, and their hourly sums were characterized by large interannual variations, and no trends could be identified between 2002 and 2020. Our study shows that there is no single mechanistic path leading from atmospheric conditions to extreme precipitation and subsequently to flash floods. The interactions between the processes involved are so intricate that more analyses which consider other potentially relevant factors, such as intra-annual precipitation patterns or catchment-specific parameters, are required.

The latitudinal dependence in the trend of snow event to precipitation event ratio

Precipitation phase is expected to shift from solid to liquid with temperature rising, which would in turn bring challenges to regional water resource management. Although in recent decades, consistent decreasing trends in the ratio of snowfall to precipitation rate in a warming climate have been found across multiple regions, a global view of the trends in the precipitation partitioning has not been established. In this study, we investigated the global trends of annual rain and snow frequency of occurrences and the ratio of number of snow events to number of precipitation events (SE/PE ratio) using land station and shipboard synoptic present weather reports from 1978 to 2019. Results show that when averaged over all qualified land stations and over the shipboard reports, both the annual rain frequency and snow frequency decrease over the 42 years. Over both land and ocean, the averaged SE/PE ratio has a significant decreasing trend. Moreover, the trend of SE/PE ratio shows a strong latitudinal dependence. At the mid- and low latitudes in the Northern Hemisphere, the SE/PE ratio has a decreasing trend. In contrast, at high latitudes, the SE/PE ratio has an increasing trend.

Dynamics and response mechanism to precipitation of farmland soil moisture

Soil moisture (SM) plays an important role in the eco-hydrological processes in the sandy land, and hence is a critical ecological limiting factor. We analyzed the farmland SM dynamics and its response to precipitation based on the 0∼160 cm SM and precipitation data from April 17 to September 15 in 2015, Horqin Sandy Land. The preliminary results shown that (1) During the experiment, the number of precipitation events was mainly <3.0 mm and accounting for 60.47% of the total precipitation events; And >15 mm occurred less and accounting for 4.65% of the total precipitation events, but its precipitation amount was relatively high (35.4 mm), accounting for 25.81% of the total precipitation. (2) With the increase of soil depth, SM firstly increased, then decrease, and finally increased again, and the SM of 40∼60 cm and 140∼160 cm soil layers were higher, while 0∼20 cm and 100∼120 cm were lower. (3) The SM was lower in April and September, and the seasonal variation of SM varies greatly depending on the soil depth. (4) After the different characteristic precipitation events, the SM of 0∼60 cm and 120∼160 cm continued to increase with the increase of soil depth, while the SM of 60∼120 cm varied with soil depth showed a more complicated trend.

Responses of grassland ecosystem productivity to altered precipitation regime: A review.

Under global change scenario, precipitation pattern has significantly changed, mainly in the aspects of annual precipitation amount, precipitation seasonal distribution and precipitation event characteristics (size of individual precipitation event, periods length between two precipitation events, and number of precipitation events in a year), which combined to affect various processes of terrestrial ecosystems, especially productivity. Grassland ecosystem is one of the most sensitive ecosystems to the changes of precipitation regime. Therefore, it is necessary to clarify the responses of productivity to altered precipitation regime in grasslands. In this study, I firstly reviewed the responses of grassland productivity to each characteristic of the altered precipitation regime. Then, I summarized the methods that employed in the study of productivity-precipitation relationship, including long-term observations, manipulative field experiments, and modelling. Finally, I came up with several theoretical and methodological problems that needed to be solved in the future. This work would facilitate the understanding of how grasslands response to the global climate change, with implications for grassland management in the context of climate change.

Spatiotemporal variations in precipitation across the Chinese Mongolian plateau over the past half century

Precipitation, as affected by climate change, controls the growth of steppe grasses and grassland degradation/desertification in semiarid/arid regions, including the Chinese Mongolian plateau. This study examined the spatial variability and temporal trends in precipitation across the plateau in terms of four indexes: total precipitation (P), number of rainy days (Wd), number of precipitation events (N), and average precipitation intensity (Imean). Although seldom published in the literature, this information is vital for efforts to develop adaptive measures to sustain this vulnerable pasture economy. Seven hundred time series were formulated by preprocessing the data on daily precipitation over the period 1960 to 2012 at 25 weather stations scattered across the plateau. The results indicated that although the plateau was becoming drier overall, the intensity of storm events increased markedly, as indicated by decreasing trends for P, Wd and N but an increasing trend for Imean. On average, P decreased by 0.65mmyr−1 over the study period, while Imean increased by 0.2mmd−1yr−1. Across the plateau, the western part was becoming wetter, while the central-eastern part was becoming drier. This spatial discrepancy in the precipitation trends was particularly obvious in the winter dry season, with Imean tending to increase more rapidly in the central-eastern than western part, especially in the spring dry season. It is expected that these trends will continue, thus further challenging the already vulnerable eco-environment of the plateau.

Impact of climate change on precipitation patterns: a comparative approach

ABSTRACTAssessment of the impact of climate change on future precipitation scenarios is critical for water resources planning and development. Despite the advances reported in climate modelling, it remains a challenge to adequately develop approaches for impact assessment that can be easily interpreted by a wide range of decision makers in the society. The future scenarios are customarily projected with a range of uncertainties. Based on a case study, this article first discusses the complementarity of different statistical tools that are relevant for assessing the impact of climate change. Then, it reports a probabilistic method, which shows promising applicability. Specifically, we address the effect of climate change over the entire range of monthly precipitation and the number of precipitation events (&gt;3 mm) across the Texas Gulf watershed. We consider daily precipitation series released by the North American Regional Climate Change Assessment Program for historical (1971–2000) and future (2041–2070) periods. The precipitation series are bias‐corrected and are then analysed using different statistical methods, including trends and pooled analyses. Subsequently, we present a probabilistic approach that is capable of depicting the plausible effects of climate change in time and space. Finally, we infer temporal changes in seasonal precipitation across the watershed, which suggest meaningful spatial disparity. The probabilistic approach may serve as a complementary tool that seems to be relevant for a holistic interpretation of critical changes in precipitation patterns under climate change.

水文気象データが乏しい流域を対象とした気候変動影響評価手法の検討

In previous studies, reanalysis data has been used instead of observation data for bias correction of GCM outputs in observation data scarece basin. However, reanalysis data does not match the real weather characteristics (e.g. precipitation, temperature) in a local scale since it is targeted at a global scale. Therefore, this study aims to develop a bias correction method for re-analysis data based on observation data. As a result, it is revealed that time-series pattern of precipitation in a reanalysis data can be corrected using three relations of monthly precipitation in reanalysis data and 1) number of precipitation events in each month, 2) average and 3) standard deviation of 6 hourly precipitation in observation data. Furthermore, it is suggested that water resources will decrease in this study site in the future by runoff analysis using GCM outputs with bias correction based on reanalysis data.

How climate change has affected the spatio‐temporal patterns of precipitation and temperature at various time scales in North Korea

ABSTRACTDetecting changes in the spatio‐temporal patterns of temperature and precipitation is a prerequisite for developing effective adaptation options and strategies for the future. An effective method for assessing climate change and for providing information to decision makers and stakeholders is needed to implement appropriate adaptation strategies. The objective of this study was to determine whether climate change has caused spatio‐temporal changes in meteorological elements in North Korea. We delineated the spatio‐temporal patterns of temperature and precipitation caused by climate change in specific time periods based on statistically significant differences using a statistically robust method. Historical weather data from 27 meteorological stations over a 30‐year period (1981–2010) were used. The results demonstrated that statistically significant changes occurred over the 30 years. The temporal trends in the maximum and minimum temperatures were highly significantly different in the western agricultural regions and central/southwest urban regions during 1996–2010 compared with 1981–1995. The precipitation amounts were significantly different in the southeast regions (around the coast). The numbers of precipitation events were significantly different for portions of the northern and northeast areas near the mountains. Additionally, statistically significant differences in the spatial structures of the temperature and precipitation were found at different time scales. The significant differences were not uniform in each season/month. Therefore, significant differences occurred in the meteorological elements, and particular locations and urbanized areas were affected by global warming. However, the temporal trends and spatial structures of each meteorological element were not equally modified; the meteorological changes occurred locally as a result of the changing climate.

Characterizing differences in precipitation regimes of extreme wet and dry years: implications for climate change experiments.

Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statistically extreme wet from extreme dry years. In general, in regions where mean annual precipitation (MAP) exceeded 1000mm, precipitation amounts in extreme wet and dry years differed from average years by ~40% and 30%, respectively. The magnitude of these deviations increased to >60% for dry years and to >150% for wet years in arid regions (MAP<500mm). Extreme wet years were primarily distinguished from average and extreme dry years by the presence of multiple extreme (large) daily precipitation events (events >99th percentile of all events); these occurred twice as often in extreme wet years compared to average years. In contrast, these large precipitation events were rare in extreme dry years. Less important for distinguishing extreme wet from dry years were mean event size and frequency, or the number of dry days between events. However, extreme dry years were distinguished from average years by an increase in the number of dry days between events. These precipitation regime attributes consistently differed between extreme wet and dry years across 12 major terrestrial ecoregions from around the world, from deserts to the tropics. Thus, we recommend that climate change experiments and model simulations incorporate these differences in key precipitation regime attributes, as well as amount into treatments. This will allow experiments to more realistically simulate extreme precipitation years and more accurately assess the ecological consequences.

Vegetation response to precipitation across the aridity gradient of the southwestern United states

Atmospheric water demand affects a variety of factors, including primary production and the terrestrial water balance. Precipitation gradients from arid to humid regions also impact the water balance and play a large role in vegetation dynamics. Focusing on a 23-year period (1989–2011), we examine precipitation during the growing season in conjunction with the Normalized Difference Vegetation Index (NDVI) series for 21 satellite scenes spanning across the southwestern United States. We classify the satellite scenes into three different groups, based on the United Nations Aridity Index (AI). Group 1 is categorized as relatively humid with AI≥0.65, group 2 is intermediate with 0.50 ≤ AI<0.65, and group 3 is relatively dry with AI<0.50. We target three types of vegetation covers: shrubland, pasture, and grassland. On a long-term basis, we find significant positive trends in the NDVI series for all types of vegetation in groups 1 and 2. The magnitude of the trend in NDVI decreases with the aridity level. However, neither the total precipitation nor the number of precipitation events (>3 mm and >13 mm) changed during this time. We also use cross-correlation analyses to establish the lagged behavior of the three types of vegetation in relation to precipitation amount and number of events. The vegetation response is similar between precipitation amount and number of precipitation events. However, in the arid region, we find distinct responses to precipitation depending on the vegetation type. The magnitude and significance of the vegetation response to precipitation patterns increase with environmental aridity. There is thus a meaningful disparity of vegetation behavior in time and space.

Analysis of watershed topography effects on summer precipitation variability in the southwestern United States

With climate change, precipitation variability is projected to increase. The present study investigates the potential interactions between watershed characteristics and precipitation variability. The watershed is considered as a functional unit that may impact seasonal precipitation. The study uses historical precipitation data from 370 meteorological stations over the last five decades, and digital elevation data from regional watersheds in the southwestern United States. This domain is part of the North American Monsoon region, and the summer period (June–July–August, JJA) was considered. Based on an initial analysis for 1895–2011, the JJA precipitation accounts, on average, for 22–43% of the total annual precipitation, with higher percentages in the arid part of the region. The unique contribution of this research is that entropy theory is used to address precipitation variability in time and space. An entropy-based disorder index was computed for each station’s precipitation record. The JJA total precipitation and number of precipitation events were considered in the analysis. The precipitation variability potentially induced by watershed topography was investigated using spatial regionalization combining principal component and cluster analysis. It was found that the disorder in precipitation total and number of events tended to be higher in arid regions. The spatial pattern showed that the entropy-based variability in precipitation amount and number of events gradually increased from east to west in the southwestern United States. Regarding the watershed topography influence on summer precipitation patterns, hilly relief has a stabilizing effect on seasonal precipitation variability in time and space. The results show the necessity to include watershed topography in global and regional climate model parameterizations.

Regional trends and local variability in monsoon precipitation in the northern Chihuahuan Desert, USA

In the southwestern United States, monsoon precipitation can affect changes to the land surface, vegetation communities and ecosystem services. To better understand monsoon precipitation, we quantified change in precipitation properties from 1910 to 2010 at 22 sites across the northern Chihuahuan Desert using United States Historical Climatology Network daily data. We also assessed precipitation variability at the Sevilleta National Wildlife Refuge (SNWR) – located at the desert's ecological boundary – using daily data from a recent 10-year period. Evaluating precipitation at these locations allows for comparison of precipitation variability between ecologically-stable ecoregions and the less-stable boundaries where ecological change may be more likely to occur. Regional data from 1910 to 2010 show an increase in the number of precipitation events, a decrease in their magnitude, and also an increase in the length of extreme periods with and without precipitation. At the SNWR, total precipitation is influenced by a small number of large events, while the majority of events (65%) have an insignificant effect. These analyses suggest that local variability in precipitation may be greater than is often attributed to the summer monsoon, and the difference between wet and dry monsoons depends on the occurrence of a small number of large events.

Diamonds and their mineral inclusions from the Renard kimberlites in Quebec

Mineral inclusions in diamonds from the Renard kimberlites, on the eastern Superior Craton, document an almost exclusively peridotitic inclusion suite with an unusually high abundance of SiO2 phases (coesite and presumably retrograde quartz). Whilst coesite is often associated with eclogitic diamond sources, there is an almost complete absence of unequivocally eclogitic mineral inclusions at Renard. Consequently, the presence of abundant SiO2 inclusion phases is likely caused by influx of CO2 within localised regions of the lithospheric mantle with very high fluid/rock ratios. This caused a progression of carbonation reactions within the host peridotite, likely along veins, locally consuming all olivine, orthopyroxene, and clinopyroxene present and producing free SiO2.Nitrogen contents and aggregation states of the diamonds indicate normal mantle residence temperatures, predominantly between 1100 and 1200°C. Co-variations of carbon isotopic composition and nitrogen content suggest formation from both reducing (CH4) and oxidising (CO32− or CO2 bearing) melts/fluids. The observation of single diamonds with non-isothermal co-variations of nitrogen content and aggregation state, or containing disequilibrium inclusion parageneses (e.g., variations in olivine Mg# up to 0.5 within single diamonds), indicates that Renard diamonds grew during a number of precipitation events within a physically and chemically changing environment.

The Effect of ENSO and PDO on Three Airborne Pollutants in Phoenix, Arizona

ABSTRACT Previous research has suggested that the El Nino-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) teleconnections have a large impact on precipitation across the Desert Southwest. El Nino years, particularly those that occur in concert with the warm phase of the PDO, have been associated with increased precipitation while La Nina years have had the opposite effect. There has been very little research examining the impact of teleconnections on pollution in the Southwest. Here, we examine the impact of both ENSO and PDO on winter pollution levels in Phoenix. By first examining the impact of precipitation events on pollution, and then by determining the impact of ENSO and PDO on the number of precipitation events, we can estimate the role of these two teleconnections on winter pollution in Phoenix. We find that ENSO and PDO have a large impact on pollution, with some pollutants increasing over 10% during La Nina compared to years experiencing El Nino.

Carbon and water exchange in semiarid ecosystems in SE Spain

The changing climate is affecting biological and physical processes occurring in the biosphere, including the biogeochemical cycles of water and carbon. The response of ecosystem carbon exchange to changes in temperature and the water balance is still very uncertain, a fact that highlights the need for research in order to understand the role of the biosphere in the future global carbon budget. South east Spain is on the borderline between the tropical and mid-latitude climate zones, with climates ranging from sub-humid to arid, and the majority representing the driest area in Europe. Initial predictions on climate change for this region point to decreases in total precipitation and the number of precipitation events, meaning a decrease in water availability underlining the vulnerability of the region to desertification. This region, due to these special climatic conditions, has been the subject of experimental carbon and water field research in recent years. This paper defines the state of the art of carbon and water balance measurement and modelling studies in this region, analyses the different processes involved in aggregate exchanges (vegetation and soil; net ecosystem carbon balance–evapotranspiration, photosynthesis–transpiration, soil respiration–evaporation), and identifies needs for future research.

Post-fire hillslope erosion response in a sub-alpine environment, south-eastern Australia

Abstract This paper examines post-fire erosion response in a sub-alpine environment in south-eastern Australia for a period of 2.2 years. Few studies have examined fire impacts on sediment transfer in this environment. Erosion pins were used in grids located at upper, mid and lower slope positions on adjacent burnt and unburnt hillslopes to assess fire effects on the extent of surface level change. The results indicated that there was a significant difference between the surface level change regimes on the burnt and unburnt hillslopes. Estimated erosion rates for the burnt slope over the study period ranged from 2.7 to 94.3 t ha − 1 , which could be considered low given the high slope angles, high precipitation and moderate fire severity. Slope position was critical in modifying post-fire erosion response, as it controlled slope angle and the rate of surface cover regrowth. Analysis of lower slope sites, for which more detailed data was available, indicated a second delayed erosion peak after the initial elevated post-fire response during the following spring snowmelt period. Surface recovery on the lower burnt site was slow, with vegetation cover still comparatively low 2.3 years after the fire. Evidence of post-fire sediment supply limitation was found on this site, with a declining rate of increase in the magnitude of total surface level change, despite limited regrowth and an increasing number of precipitation events > 20 mm for measurement intervals since the fire. Modification of the hillslope surface by fire leads to changing hillslope erosion process dominance in this environment. The post-fire hillslope undergoes erosion by direct rain-drop impact and overland flow, whereas the unburnt slope rarely experiences overland flow due to the thick ground cover. As a result surface level change on the unburnt slope was largely influenced by wetting–drying effects rather than sediment transfer by surface flow. Downslope biotransfer appears to be the dominant sediment movement process in the unburnt sub-alpine forest environment.

How long must a desiccation‐tolerant moss tolerate desiccation? Some results of 2 years' data logging on Grimmia pulvinata

Grimmia pulvinata (Hedw.) Sm. is a common desiccation‐tolerant moss of wall tops in Britain. Readings were recorded at 30‐min intervals from sensors measuring duration of precipitation, ‘moss wet’, solar irradiance, net radiation, air temperature and moss temperature. The duration of both ‘moss‐dry’ and ‘moss‐wet’ periods varied widely, but generally approximated to a log‐normal frequency distribution. The median length of dry and wet periods was relatively short, generally between 5 and 15 h. The longest dry periods, recorded in early summer, were 15 and 17 days, and the longest continuously wet period (almost 28 d), in the unusually wet autumn of 1988. The moss was generally wet for longer than the duration of rain by an average factor of 1.7, and the number of dry–wet cycles less than the number of precipitation events by a factor of 3 or more, especially during autumn and winter. There was little indication of hydration following dew‐fall. The proportion of the time the moss was wet in daylight at any time of year was nearly proportional to the fraction of the 24 h between sunrise and sunset. Most growth took place in autumn and early winter when (with relatively low irradiance) the moss was wet for long periods and the weather was still mild. Desiccation‐tolerant bryophytes (and lichens) are pre‐eminently organisms adapted to frequent, and often short, dry–wet cycles. This should be a prime focus of research on their physiology.

The temporal and spatial variability of sediment transport and yields within the Bradford Beck catchment, West Yorkshire

Recent EU directives have emphasised the need to understand and limit potential water quality problems within urban river systems. Under certain conditions sediments and contaminants derived from industrial and domestic waste and the urban surface may be expelled into urban rivers via the sewer and drainage system. These discharges may lead to water quality problems within urban catchments. One aspect of water quality is the suspended sediment. This can be directly detrimental to water quality by affecting the habitat for fish and other biota but it is also closely associated with pollutants, such as heavy metals, which may be adsorbed onto the sediments surface. This paper presents a comparative analysis of sediment yields for a small mixed rural/urban catchment, the Bradford Beck in West Yorkshire, over a number of precipitation events. Flow and water quality parameters were monitored at a high temporal resolution at strategic sites within the urban watercourse over a 2-year period. Rainfall was measured at six locations within the catchment. Analysis of discrete rainfall events allowed an understanding of the temporal and spatial variability of sediment transport within the catchment to be developed. The results demonstrated that for individual storms the sediment yields from the urban sub-catchment were generally higher than those from the rural system although the annual yields were comparable. Sediment transport within the urban area, for large events, was dominated by the impact of the Combined Sewer Overflows discharging. Within these events peak suspended sediment concentration, SSC, were generally higher than the rural system. Within smaller events the main sediment source within the urban area was the surface runoff discharging directly to the urban river. Analysis of SSC and discharge relationships illustrated the different sources of sediment for contrasting events. Within the rural system clockwise hysteresis, indicating exhaustion of sediment supply, was noted for larger storms. The high temporal resolution monitoring has enabled a better understanding of sediment dynamics within the Bradford Beck system to be developed. The general conclusions drawn can provide guidance for addressing sediment related water quality issued in other urban systems.

시간강수계열의 강수발생과정에 대한 추계학적 모형

This study is an effort to develop a stochastic model of precipitation series that preserves the pattern of occurrence of precipitation events throughout the year as well as several characteristics of the duration, amount, and intensity of precipitation events. In this study an event cluster model is used to describe the occurrence of precipitation events. A logarithmic negative mixture distribution is used to describe event duration and separation. The number of events within each cluster is also described by the Poisson cluster process. The duration of each event within a cluster and the separation of events within a single cluster are described by a logarithmic negative mixture distribution. The stochastic model for hourly precipitation occurrence process is fitted to historical precipitation data by estimating the model parameters. To allow for seasonal variations in the precipitation process, the model parameters are estimated separately for each month. an analysis of thirty-four years of historical and simulated hourly precipitation data for Seoul indicates that the stochastic model preserves many features of historical precipitation. The seasonal variations in number of precipitation events in each month for the historical and simulated data are also approximately identical. The marginal distributions for event characteristics for the historical and simulated data were similar. The conditional distributions for event characteristics for the historical and simulated data showed in general good agreement with each other.

Climate change in the semiarid prairie of southwestern Saskatchewan: Temperature, precipitation, wind, and incoming solar energy

Long-term weather data were analyzed to study annual as well as seasonal climate change within an approximately 15 000-km2 area in the semiarid prairie near Swift Current, SK. The climate of the study region has changed over the past 50 yr. Annually, average maximum (Tmx) and minimum (Tmn) air temperatures have increased – rainfall amounts and the number of rainfall events (≥0.5 mm) have increased since the late 1960s-early 1970s; incoming solar energy has decreased, and wind speed has decreased since the early 1970s. Seasonally, for January through April (JFMA), both Tmx and Tmn have increased, the number of rainfall events has increased since the early 1970s, snowfall amounts and the number of snowfall events (≥0.5 cm) have decreased; the number of precipitation events (≥0.5 mm) has decreased, incoming solar energy has decreased, and wind speed has decreased since the early 1970s. For May through August (MJJA), Tmn has increased, incoming solar energy has decreased, and wind speed has decreased since the mid-1970s. For September through December (SOND), the number of rainfall events has increased since the early 1970s and wind speed has decreased. Since 1950, JFMA has become drier and, relative to JFMA, SOND has become wetter. Generally, JFMA has experienced the largest change in climate, whereas SOND has experienced the least climate change. Precipitation amounts and events were negatively correlated with increasing Tmx, suggesting a future decrease in precipitation amounts for southwestern Saskatchewan if global warming continues. Key words: Climate change, semiarid prairie, temperature, precipitation, wind, solar energy