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<strong class="journal-contentHeaderColor">Abstract.</strong> Understanding the differences between regional simulations of land–atmosphere interactions and near-surface conditions is crucial for a more reliable representation of past and future climate. Here, we explore the effect of changes in the model's horizontal resolution on the simulated energy balance at the surface and near-surface conditions using the Weather Research and Forecasting (WRF) model. To this aim, an ensemble of 12 simulations using three different horizontal resolutions (25, 50 and 100 <span class="inline-formula">km</span>) and four different land surface model (LSM) configurations over North America from 1980 to 2013 is developed. Our results show that finer resolutions lead to higher surface net shortwave radiation and maximum temperatures at mid and high latitudes. At low latitudes over coastal areas, an increase in resolution leads to lower values of sensible heat flux and higher values of latent heat flux, as well as lower values of surface temperatures and higher values of precipitation, and soil moisture in summer. The use of finer resolutions leads then to an increase in summer values of latent heat flux and convective and non-convective precipitation and soil moisture at low latitudes. The effect of the LSM choice is larger than the effect of horizontal resolution on the near-surface temperature conditions. By contrast, the effect of the LSM choice on the simulation of precipitation is weaker than the effect of horizontal resolution, showing larger differences among LSM simulations in summer and over regions with high latent heat flux. Comparison between observations and the simulation of daily maximum and minimum temperatures and accumulated precipitation indicates that the CLM4 LSM yields the lowest biases in maximum and minimum mean temperatures but the highest biases in extreme temperatures. Increasing horizontal resolution leads to larger biases in accumulated precipitation over all regions particularly in summer. The reasons behind this are related to the partition between convective and non-convective precipitation, specially noticeable over western USA.

&amp;lt;p&amp;gt;Interactions between the lower atmosphere and the shallow continental subsurface govern several surface processes important for ecosystems and society, such as extreme temperature and precipitation events. Transient climate simulations performed with climate models have been employed to study the water, mass and energy exchanges between the atmosphere and the shallow subsurface, obtaining large inter-model differences. Understanding the origin of differences between climate models in the simulation of near-surface conditions is crucial for restricting the inter-model variability of future climate projections. Here, we explore the effect of changes in horizontal resolution on the simulation of the surface energy balance and the climatology of near-surface conditions over North America (NA) using the Weather Research and Forecasting (WRF) model.&amp;amp;#160;&amp;lt;br&amp;gt;We analyzed an ensemble of twelve simulations using three different horizontal resolutions (25 km, 50 km and 100 km) and four different Land Surface Model (LSM) configurations over North America from 1980 to 2013. Our results show that increasing horizontal resolution alters the representation of shortwave radiation, affecting near-surface temperatures and consequently the partition of energy into sensible and latent heat fluxes. Thus, finer resolutions lead to higher net shortwave radiation and temperature at high NA latitudes and to lower net shortwave radiation and temperature at low NA latitudes. The use of finer resolutions also leads to an intensification of the terms associated with the surface water balance over coastal areas at low latitudes, generating higher latent heat flux, accumulated precipitation and soil moisture. The effect of the LSM choice is larger than the effect of horizontal resolution on the representation of the surface energy balance, and consequently on near-surface temperature. By contrast, the effect of the LSM configuration on the simulation of precipitation is weaker than the effect of horizontal resolution, showing larger differences among LSM simulations in summer and over regions with high latent heat flux. This ensemble of simulations is then compared against CRU data. Comparison between the CRU data and the simulated climatology of daily maximum and minimum temperatures and accumulated precipitation indicates that enhancing horizontal resolution marginally improves the simulated climatology of minimum and maximum temperatures in summer, while it leads to larger biases in accumulated precipitation. The larger biases in precipitation with the use of finer horizontal resolutions are likely related to the effect of increasing resolution on the atmospheric model component, since precipitation biases are similar using different LSM configurations.&amp;lt;/p&amp;gt;

Impacts of soil moisture content on simulated mesoscale circulations during the summer over eastern Spain

In the present work, we report daytime latent heat flux profile measurements in the convective boundary layer (CBL) obtained from the combined use of a wind lidar and a thermodynamic Raman lidar. Water vapour flux profiles and, consequently, latent heat flux profiles were obtained as the covariance between the vertical profiles of the water vapour mixing ratio and vertical wind fluctuations. Profile measurements of the water vapour mixing ratio were carried out by the thermodynamic Raman lidar CONCERNING, while simultaneous profile measurements of the vertical wind speed were carried out by a co-located Doppler wind lidar. The considered dataset was collected in the frame of the international field campaign “Water Vapor Lidar Network Assimilation” (WaLiNeAs). Three cloud-free time intervals on 31 October, 28 November, and 8 December 2022 were selected as case studies. Measurements of turbulent kinetic energy (TKE) were also carried out over the same time intervals based on the use of wind lidar data. The three selected case studies were characterised by different atmospheric stability conditions and, consequently, by a different potential for the occurrence of convective activity. More specifically, the atmospheric conditions on 31 October 2022 were very unstable, with intensive convective activity taking place in the area and ultimately leading to relatively intense thunderstorms and rainfall events. The atmospheric conditions on 28 November 2022 were moderately unstable, ultimately leading to light convective activity, with scattered rain episodes observed throughout the day but with no severe thunderstorms taking place. Stratiform precipitations were present on 8 December 2022, with weak embedded convective processes taking place within stratiform clouds and leading to moderate additional precipitation. In all three selected case studies, representative of pre-convective conditions, both latent heat flux and TKE profiles are characterised by values increasing with altitude up to approx. 500 m, while both latent heat flux and TKE are found to decrease, with a steeper negative gradient up to approx. 600 m and more gradually above this altitude, returning to zero just above the top of the CBL. In all three cases, peak values of TKE appear to be strongly correlated with corresponding peak values of the latent heat flux; the higher the maximum values of TKE and latent heat flux, the more intense the following precipitation events.

The evapotranspiration (ETc) of sprinkler-irrigated rice was determined for the semiarid conditions of NE Spain during 2001, 2002 and 2003. The surface renewal method, after calibration against the eddy covariance method, was used to obtain values of sensible heat flux (H) from high-frequency temperature readings. Latent heat flux values were obtained by solving the energy balance equation. Finally, lysimeter measurements were used to validate the evapotranspiration values obtained with the surface renewal method. Seasonal rice evapotranspiration was about 750–800 mm. Average daily ETc for mid-season (from 90 to 130 days after sowing) was 5.1, 4.5 and 6.1 mm day−1 for 2001, 2002 and 2003, respectively. The experimental weekly crop coefficients fluctuated in the range of 0.83–1.20 for 2001, 0.81–1.03 for 2002 and 0.84–1.15 for 2003. The total growing season was about 150–160 days. In average, the crop coefficients for the initial (Kcini), mid-season (Kcmid) and late-season stages (Kcend) were 0.92, 1.06 and 1.03, respectively, the length of these stages being about 55, 45 and 25 days, respectively.

Sea-effect snow (SES) is a meteorological phenomenon resulting from cold air moving over warmer waters. Accurate prediction of SES is vital for emergency management, transportation, and water resource planning. A thundersnow event in Istanbul from 17–19 February 2015 caused significant disruptions, with traffic and flights affected, highways temporarily closed, and trees falling due to heavy snowfall. This study investigates the influence of different parameterization schemes in the Weather Research and Forecasting (WRF) model on SES simulations. Six distinct PBL parameterization schemes were used in a series of WRF simulations. In addition, the following factors pivotal to SES event have also been investigated: 1000–500 hPa thickness, total and latent heat fluxes, radar and satellite analyses, temperature gradients, wind shear, inversion levels, and atmospheric stability indices. Additionally, the formation of SES during the cold front transition further contributed to these elements in the Black Sea region. The simulations displayed notably high total heat flux and latent heat flux values, particularly following the passage of the cold front. Furthermore, the northeast-southwest oriented SES cloud, distinguished by its banded structure, was successfully validated using radar and satellite imagery. However, it's worth noting that the model positioned it farther west than its actual location. This study highlights the challenges in precise prediction and analysis of such convective activities. In this thundersnow event, the local closure schemes, particularly MYNN in first place and second MYJ, demonstrated superior performance compared to non-local schemes within the parameterization options.

This paper examines the expected future heat load in five Croatian cities: Dubrovnik, Zadar, Rijeka, Zagreb, and Osijek. The heat load is estimated by temperature-related climate indices and mean, maximum and minimum daily temperatures obtained by climate simulations using two different regional climate models (DHMZ-RegCM4 and SMHI-RCA4) with a horizontal resolution of 12.5 km, forced with two global climate models (EC-EARTH and MPI-ESM-MR/LR) for two different greenhouse gas concentration scenarios (RCP4.5 and RCP8.5). By comparing these variables for the period 2041–2070 with respect to the current climate (defined as that of the period 1991–2020), a significant increase in mean, maximum and minimum temperatures was observed in all analysed combinations of regional and global climate models for all analysed cities. Although there is a difference in results depending on the combination of regional and global models, the largest increase is mainly found in the warm part of the year (April-October), with the strongest warming of Dubrovnik and Rijeka. Due to similar trends in minimum and maximum temperatures, the trend in the daily temperature range is weak. Under warmer climate conditions, the number of days with a maximum air temperature above 25 °C increases in all considered cities (especially in Dubrovnik), as does the number of days with a minimum air temperature exceeding 20 °C (especially in Rijeka and Zadar). Furthermore, a reduction in the number of days with maximum and minimum temperatures below 0 °C is projected for all cities. Nevertheless, some differences are found between coastal and inland cities caused by local factors.

سابقه و هدف: در سال‌های اخیر مدل‌های هیدرولوژیکی مانند مدل SWAT به‌عنوان ابزاری برای شناخت فعالیت‌های طبیعی و انسانی موثر بر سیستم هیدرولوژی حوضه و مدیریت و برنامه‌ریزی آنها، به‌طور گسترده توسط مدیران و هیدرولوژیست‌ها به‌کار گرفته شد. با توجه به اینکه دشت‌های شرق مازندران، تنها منطقه ممنوعه برداشت آب زیرزمینی در شمال کشور است، بنابراین با پیش‌بینی دقیق جریان ورودی به سد گلورد برای دوره‌های آتی می‌توان برنامه‌ریزی دقیقی برای تامین منابع آبی پایین‌دست داشت و تقاضا برای آب و توسعه کشاورزی را مدیریت نمود. لذا هدف این پژوهش بررسی تاثیر تغییر اقلیم بر نوسانات دبی جریان سد گلورد در شرق استان مازندران است. مواد و رو‌ش‌ها: در این پژوهش از دو مدل HadGEM2 و EC-Earth، برای تولید داده‌های دمای کمینه و بیشینه و بارش در دوره‌ 2021-۲۰40 از ترکیب داده‌های ایستگاه برما و داده‌های جهانی در محل سد گلورد استفاده شد. جهت ریزمقیاس نمودن این داده‌ها مدل LARS-WG6 بکار گرفته شد. همچنین برای بررسی روند پارامترهای اقلیمی از آزمون من-کندال و شیب سن استفاده شده است. سپس اطلاعات به مدل SWAT که با استفاده از داده‌ها و اطلاعات محلی واسنجی (از سال 1984 تا 2010 برای واسنجی و 2011 تا 2014 برای صحت‌سنجی) شده بود، وارد شده و تغییرات رواناب نیز مورد ارزیابی قرار گرفت. دقت مدل SWAT در شبیه‌سازی جریان خروجی به کمک نمایه‌های ارزیابی بررسی شد. یافته‌ها: نتایج نشان داد که پدیده تغییر اقلیم تبعات منفی بر منطقه‌ی سد گلورد دارد که باعث افزایش کمینه و بیشینه دما به‌ترتیب به مقدار 40/1 و 40/2 درجه سانتی‌گراد می‌شود. مدل SWAT زمان وقوع دبی اوج و مقادیر دبی اوج را به‌طور مناسبی شبیه‌سازی کرده است به‌طوری‌که با زمان رخداد بارندگی شدید مطابقت دارد. مقایسه اثرات بارش و دمای کمینه و بیشینه بر جریان خروجی، حاکی از تاثیرات بیشتر دما نسبت به بارش بر جریان خروجی است، به‌طوری که در دوره پایه، کمینه دما برابر 41/1 و بیشینه دما برابر 34/2 بوده ‌است. همچنین تغییرات دبی‌های متوسط ماهانه در سناریوهای RCP4.5 (01/0-) و RCP8.5 (11/0-) نسبت به دبی‌های مشاهداتی (16/0-) کمتر است و در ماه‌های گرم سال، دبی خروجی کاهش یافته ‌است. با بررسی درصد اختلاف بیشینه و کمینه دما و بارندگی تحت سناریوهای RCP4.5 و RCP8.5 در مقایسه با دوره پایه مشخص شد که افزایش دما، بیشتر باعث کاهش دبی خروجی در دوره آینده شده است. به‌طوری که اثر تغییر اقلیم بر فرایند بارش-رواناب باعث کاهش 13 درصدی منابع آبی سد گلورد شد. نتایج آنالیز حساسیت نشان داد که ضریب تبخیر خاک، متوسط طول (شیب)، متوسط دمای هوا برای بارش برف (درجه سلسیوس) و شماره منحنی در شرایط رطوبتی، بیشترین تاثیر را روی دبی خروجی داشته است. نتیجه‌گیری: نتایج به‌دست‌آمده صرف‌نظر از جهت تغییرات هر یک از مولفه‌ها، دلالت بر اهمیت الگوی زمانی تغییرات در طول سال دارد که نقش موثری در مدیریت منابع آب حوضه دارا است. نتایج پژوهش حاضر ضمن بیان اهمیت اثرات بالقوه تغییر اقلیم در وضعیت هیدرولوژی حوضه، لزوم توجه به بحث تغییر اقلیم و پیامدهای آن را در مدیریت منابع آب سد گلورد متذکر می‌گردد.

Assessment of the land surface models (LSMs) on monsoon studies over the Indian summer monsoon (ISM) region is essential. In this study, we evaluate the skill of LSMs at 10 km spatial resolution in simulating the 2010 monsoon season. The thermal diffusion scheme (TDS), rapid update cycle (RUC), and Noah and Noah with multi-parameterization (Noah-MP) LSMs are chosen based on nature of complexity, that is, from simple slab model to multi-parameterization options coupled with the Weather Research and Forecasting (WRF) model. Model results are compared with the available in situ observations and reanalysis fields. The sensitivity of monsoon elements, surface characteristics, and vertical structures to different LSMs is discussed. Our results reveal that the monsoon features are reproduced by WRF model with all LSMs, but with some regional discrepancies. The model simulations with selected LSMs are able to reproduce the broad rainfall patterns, orography-induced rainfall over the Himalayan region, and dry zone over the southern tip of India. The unrealistic precipitation pattern over the equatorial western Indian Ocean is simulated by WRF–LSM-based experiments. The spatial and temporal distributions of top 2-m soil characteristics (soil temperature and soil moisture) are well represented in RUC and Noah-MP LSM-based experiments during the ISM. Results show that the WRF simulations with RUC, Noah, and Noah-MP LSM-based experiments significantly improved the skill of 2-m temperature and moisture compared to TDS (chosen as a base) LSM-based experiments. Furthermore, the simulations with Noah, RUC, and Noah-MP LSMs exhibit minimum error in thermodynamics fields. In case of surface wind speed, TDS LSM performed better compared to other LSM experiments. A significant improvement is noticeable in simulating rainfall by WRF model with Noah, RUC, and Noah-MP LSMs over TDS LSM. Thus, this study emphasis the importance of choosing/improving LSMs for simulating the ISM phenomena in a regional model.

Northeast Ethiopia is a semi-arid region that exhibits high rainfall and temperature variability. The impact of climate change has received a great deal of attention worldwide. This study focused on detecting trends in in rainfall (1983-2013) and temperature (1981-2010) at annual, seasonal and monthly time scales for six weather stations in semi-arid north eastern Ethiopia. The study also aimed to determine dry spell length, number of rainy days, onset and cessation dates, and length of growing period. The non-parametric tests such as Mann-Kendall and Sen’s Slope were used to determine climatic trends. The results indicated that both the annual maximum and minimum temperature in the study region showed an increasing trend, but only the trend for maximum temperature was significant. In the same manner, both the Belg and Kiremt seasons maximum and minimum temperature also showed an increasing trend but only trend of maximum temperature during Belg season and trend of minimum and maximum temperature during Kiremt seasons was significant. The annual and Belg season rainfall in the region showed a decreasing trend and its trend was significant. The coefficient of rainfall variability for annual and Belg season was very high which could affect agricultural production in the region. In the contrary, the trend for Kiremt season rainfall was increasing without significant trend. On the other hand, the average length of dry spell during the Kiremt season in the region was generally long that ranged from 27 days to 39 days and showed both decreasing and increasing but with no significant trend in most stations. The number of annual rainy days also showed both increasing and decreasing trends but its trend was not significant. The length of growing period in the region was relatively stable at all stations during the last 30 years period without non-significant trend. In general, from the analysis of annual, seasonal and monthly rainfall and temperature data series it can be concluded that rainfall and temperature characteristics of the study area is changing, even though some of the trends on both parameters were not statistically significant.

Climate variability presents novel challenges to the conservation of maritime cultural and natural heritage. In the south Kenya coast, responses to extreme temperatures and sudden onset high rainfall worsen the condition of historic buildings and sacred landscapes, putting maritime communities at risk. To provide a baseline for prioritizing conservation planning initiatives, the paper sought to establish climate variability for the adaptation of maritime heritage to climate change. Between 1994 and 2024, average maximum and minimum temperatures rose by +1.6°C and +1.4°C, respectively. Linear regressions of average maximum and minimum temperatures showed high extremes of 32.10°C to 32.40°C and low extremes of 19.8°C to 20°C, respectively. The leptokurtic distribution showed a substantial chance of severe outcomes in average minimum and maximum temperatures in September and November, respectively. Over 30 years, the average maximum rainfall increased by 190mm with linear regressions indicating high extremes between 1500mm and 1600mm. The leptokurtic distribution revealed a substantial chance of extreme outcomes in average maximum rainfall in November. Average maximum and minimum temperatures for the final two years were considerably higher than the first two years; t (-5.2086, 1.0000) = 6.3138, P=0.0604) and t (--3.7226, 1.0000) = 6.3138, P=0.0835). However, average mean rainfall over the first two years was significantly lower than that over the latter two years t (-0.525, 1.000) = 6.3138, P =0.3460). Overall, unpredictability of short and long rainy seasons has increased during the last ten years compared to the previous twenty. Conservation planning is to consider physical stabilizations, shoreline consolidation, mangrove restoration, land use control, adjustments of setbacks and buffer zones to adapt maritime heritage to climate change.

This study explores the impact of land-use and land-cover (LULC) changes due to different urbanization scenarios in the Delhi–Mumbai Industrial Corridor (DMIC) region on surface air temperature by conducting sensitivity studies with the Weather Research and Forecasting (WRF) model. First, a sensitivity analysis conducted using the planetary boundary layer (PBL) and surface layer (SL) physical parameterizations available in WRF. Results show that the model performs better when a combination of the Mellor–Yamada–Janjic PBL and ETA SL schemes used. Then, numerical experiments performed using WRF with the above configuration and three different LULC scenarios to assess the possible impact of urbanization on near-surface temperature during May. A total of ten simulations were conducted for the May month of 2005–2014 to estimate the statistical and physical robustness of results. Each of these simulations considered as ensemble member while computing average values. The study shows that there is a significant effect of LULC change mainly on the minimum temperature (Tmin) with an increase of 2.9–3.7℃ over the DMIC region. The impact is less on maximum temperature, with a minor rise in 0.1–0.3℃. The probable reason for the increase in minimum temperature is likely due to a decrease in latent heat flux and an increase in sensible heat flux. The impact on air temperature was found to be prominent over existing urban clusters than the surrounding built environment; also, this effect is additive and more pronounced with the extreme LULC change scenario.

The influence of temperature on tuber yield and development of internal heat necrosis (IHN) in Atlantic (Solanum tuberosum L.) was examined in field trials in two locations over three years (seven plantings). Under simulated commercial production, yield and development of IHN varied significantly between Virginia (VA) and New Jersey (NJ) in 1986, 1987, and 1988. Marketable yield ranged from 49.8 mt.ha−1 for the early planting in 1986 in New Jersey (NJ86E) to 17.9 for VA87. Tubers developing IHN to a level which potato chip processors would rate unacceptable (off-grade) varied with year and location. Significant correlations were found between the number of days to off-grade and the mean maximum temperature for 0–30 (r = −.83), 30–60 (r = −.86) and 60–90 DAP (r = −.81) as well as the mean minimum temperature for the same periods (r = −.91,, −.80 and −.91, respectively). The relationship between yield or IHN and temperature was examined using heat-sum models with a penalty for maximum daily temperature > 25C but with or without a penalty for minimum temperature > 21C. The multiple coefficients of determination for yield were similar using either variables generated from the heat-sum model with maximum and minimum temperature penalties or from the model with maximum temperature penalty only (R2 = 0.83 and R2 = 0.82). The prediction of the time from first symptom of necrosis to off-grade (interval) was improved by including variables generated by the heat-sum model that included both the minimum and maximum temperature penalty (R2 = 0.50 vs. R2 = 0.27), respectively. High minimum temperatures as reflected in the days to maximum heat-sum were found to significantly affect tuber yield and the expression and development of IHN.

ABSTRACTThis study investigates the impacts of climate change scenario on summer heat waves' (HWs) and winter cold spells' (CSs) characteristics for 12 locations over the Iberian Peninsula (IP). These characteristics are duration, recovery factor and intensity. Two future time slices of the chosen scenario are studied, namely, the periods 2046–2065 and 2081–2100 which are compared with a reference climate for the recent‐past (1986–2005). TheRCP8.5 greenhouse gas emission scenario is considered. The minimum and maximum daily temperature were obtained for these periods through regional model simulations using the Weather and Research Forecast (WRF) model forced with theMPI‐ESM‐LRmodel. The model was validated againstEOBSandSPAIN02datasets. The model shows 90th/10th percentile temperature (i.e. thresholds to identifyHW/CS) biases. Therefore,HW/CSnumbers and properties were evaluated using the model's respective thresholds.HW/CSnumbers and characteristics were also compared between the model andEOBSderived data. Probability density functions (PDFs) of the duration, recovery factor and intensity show significant changes in the mean and variance for the summerHWs. Differences, between future and recent‐past climate in the extremes are evaluated by the 95th percentile which show an increase in the duration and intensity of theHWsfor the future time slices. Very fewCSswere detectable in the mid‐term future (2046–2065) and none in the long‐term future (2080–2100), except for Barcelona. For most locations, theCSfor the future are of smaller duration and intensity. ThePDFof the recovery factor suggests smaller absolute differences between the minimum and maximum temperature during winter which is also confirmed by the percentile analysis. The increase in the duration and intensity ofHWsis greater in the long‐term future than in the mid‐term future, pointing for a warmerIPwith more and longerHWstowards the end of theXXIcentury.

The New England region of the northeastern United States has a land use history characterized by forest clearing for agriculture and other uses during European colonization and subsequent reforestation following widespread farm abandonment. Despite these broad changes, the potential influence on local and regional climate has received relatively little attention. This study investigated wintertime (December through March) climate impacts of reforestation in New England using a high-resolution (4 km) multiphysics ensemble of the Weather Research and Forecasting Model. In general, the conversion from mid-1800s cropland/grassland to forest led to warming, but results were sensitive to physics parameterizations. The 2-m maximum temperature (T2max) was most sensitive to choice of land surface model, 2-m minimum temperature (T2min) was sensitive to radiation scheme, and all ensemble members simulated precipitation poorly. Reforestation experiments suggest that conversion of mid-1800s cropland/grassland to present-day forest warmed T2max +0.5 to +3 K, with weaker warming during a warm, dry winter compared to a cold, snowy winter. Warmer T2max over forests was primarily the result of increased absorbed shortwave radiation and increased sensible heat flux compared to cropland/grassland. At night, T2min warmed +0.2 to +1.5 K where deciduous broadleaf forest replaced cropland/grassland, a result of decreased ground heat flux. By contrast, T2min of evergreen needleleaf forest cooled –0.5 to –2.1 K, primarily owing to increased ground heat flux and decreased sensible heat flux.