Daily Temperature Values Research Articles

The effect of stimulants and environmental factors on resin yield of Pinus merkusii tapping

Oleoresin from Pinus merkusii is one of the most important forest products in Indonesia. The objective of this study was to examine the effects of various stimulants and environmental factors on oleoresin yield. The first factor was the stimulant treatment, i.e., SAEt1 (20% sulfuric acid + 1% Ethephon); SAEt2 (20% sulfuric acid + 2% Ethephon); SR4 (mainly composed by sulfuric acid); ETRAT (mainly composed by ethylene and citric acid); and without stimulant spraying. The second factor was the site with different altitudes, i.e., West Banyumas (326 m asl), East Banyumas (797 m asl), and West Pekalongan (1150 m asl). Through analysis of variance, the relation between stimulant and site was highly significant in regards to the average daily oleoresin yield. The results indicated that the combination of sulfuric acid and Ethephon increased oleoresin production 1.69- to 2.85-fold compared with untreated trees, depending on the sites. The trees with SAEt1 and SAEt2 treatments yielded an equivalent amount of oleoresin compared to that of trees exposed to the SR4. The ETRAT showed the lowest resin yields compared to the other stimulants. The values of daily relative humidity and temperature did not show similar responses in all sites when correlated with daily oleoresin yield.

Modeling and projecting health-relevant combined ozone and temperature events in present and future Central European climate

Statistical models to evaluate the relationships between large-scale meteorological conditions, prevailing air pollution levels and combined ozone and temperature events, were developed during the 1993–2012 period with Central Europe as regional focus. Combined ozone and temperature events were defined based on the high frequency of coinciding, health-relevant elevated levels of daily maximum tropospheric ozone concentrations (based on running 8-h means) and daily maximum temperature values in the peak ozone and temperature season from April to September. By applying two different modeling approaches based on lasso, logistic regression, and multiple linear regression mean air temperatures at 850 hPa, ozone persistence, surface thermal radiation, geopotential heights at 850 hPa, meridional winds at 500 hPa, and relative humidity at 500 hPa were identified as main drivers of combined ozone and temperature events. Statistical downscaling projections until the end of the twenty-first century were assessed by using the output of seven models of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Potential frequency shifts were evaluated by comparing the mid- (2031–2050) and late-century (2081–2100) time windows to the base period (1993–2012). A sharp increase of ozone-temperature events was projected under RCP4.5 and RCP8.5 scenario assumptions with respective multi-model mean changes of 8.94% and 16.84% as well as 13.33% and 37.52% for mid- and late-century European climate.

Dynamical climatic model for time to flowering in Vigna radiata

BackgroundPhenology data collected recently for about 300 accessions of Vigna radiata (mungbean) is an invaluable resource for investigation of impacts of climatic factors on plant development.ResultsWe developed a new mathematical model that describes the dynamic control of time to flowering by daily values of maximal and minimal temperature, precipitation, day length and solar radiation. We obtained model parameters by adaptation to the available experimental data. The models were validated by cross-validation and used to demonstrate that the phenology of adaptive traits, like flowering time, is strongly predicted not only by local environmental factors but also by plant geographic origin and genotype.ConclusionsOf local environmental factors maximal temperature appeared to be the most critical factor determining how faithfully the model describes the data. The models were applied to forecast time to flowering of accessions grown in Taiwan in future years 2020-2030.

Characterization of long period return values of extreme daily temperature and precipitation in the CMIP6 models: Part 2, projections of future change

Using a non-stationary Generalized Extreme Value statistical method, projected future changes in selected extreme daily temperature and precipitation indices and their 20 year return values from the CMIP5 and CMIP6 climate models are calculated and compared. Projections are framed in terms of specified global warming target temperatures rather than at specific times and under specific emissions scenarios. The change in framing shifts projection uncertainty due to differences in model climate sensitivity from the values of the projections to the timing of the global warming target. At their standard resolutions, there are no meaningful differences between the two generations of models in their projections of simulated extreme daily temperature and precipitation at specified global warming targets.

Characterization of long period return values of extreme daily temperature and precipitation in the CMIP6 models: Part 1, model evaluation

Using a non-stationary Generalized Extreme Value statistical method, we calculate selected extreme daily temperature and precipitation indices and their 20 year return values from the CMIP5 and CMIP6 historically forced climate models. We evaluate model performance of these indices and their return values in replicating similar quantities calculated from gridded land based daily observations. We find that at their standard resolutions, there are no meaningful differences between the two generations of models in their quality of simulated extreme daily temperature and precipitation.

CHANGES IN SUMMER AND TROPICAL DAYS AT THE LAKES DISTRICT OF THE MEDITERRANEAN REGION OF TURKEY BETWEEN THE PERIOD OF 1969-2014

Summer and tropical days are determined about the daily maximum air temperature values. Examining the annual numbers of summer and tropical days is one of the methods to reveal changes and trends in air temperatures and therefore in climate on a global, regional and local scale. This study aims to examine the long-term changes and trends of the annual numbers of summer and tropical days of the Lakes District of Turkey, which is located in the transition zone between Mediterranean climate and Central Anatolia continental climate between the period of 1969–2014 at 11 meteorological stations. Singular scanning method was used in the study. The results suggest that the numbers of summer and tropical days changed within the years of the period examined. In the analyzed period, it has been determined that the annual numbers of summer and tropical days and the annual numbers of tropical days change within years and periods, and show an increase, and trend lines also indicate an increase. It was determined that the number of tropical days showed a significant increase trend in all stations and in the average of the study area. Also, it has been determined that the annual numbers of summer days generally decrease over the years and periods and the trend lines also indicate a decrease. The number of summer days shows a decreasing trend that is not significant in Beyşehir, Eğirdir and Uluborlu stations, but significant in other stations and in the average of the study area. The increasing trend in tropical days can be considered as a potential risk for human health and activities and natural environment.

Does weather trigger urologic chronic pelvic pain syndrome flares? A case-crossover analysis in the multidisciplinary approach to the study of the chronic pelvic pain research network.

To investigate whether meteorological factors (temperature, barometric pressure, relative humidity, ultraviolet index [UVI], and seasons) trigger flares in male and female urologic chronic pelvic pain patients. We assessed flare status every 2 weeks in our case-crossover study of flare triggers in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain 1-year longitudinal study. Flare symptoms, flare start date, and exposures in the 3 days preceding a flare or the date of questionnaire completion were assessed for the first three flares and at three randomly selected nonflare times. We linked these data to daily temperature, barometric pressure, relative humidity, and UVI values by participants' first 3 zip code digits. Values in the 3 days before and the day of a flare, as well as changes in these values, were compared to nonflare values by conditional logistic regression. Differences in flare rates by astronomical and growing seasons were investigated by Poisson regression in the full study population. A total of 574 flare and 792 nonflare assessments (290 participants) were included in the case-crossover analysis, and 966 flare and 5389 nonflare (409 participants) were included in the full study analysis. Overall, no statistically significant associations were observed for daily weather, no patterns of associations were observed for weather changes, and no differences in flare rates were observed by season. We found minimal evidence to suggest that weather triggers flares, although we cannot rule out the possibility that a small subset of patients is susceptible.

High-resolution simulations with COSMO model including TERRA_URB TERRA_URB parameterization for the representation of Urban Heat Islands over South Italy

Abstract. In this work, some preliminary numerical simulations with the COSMO model including TERRA_URB parameterization have been performed. In particular, this work concerns simulations over a small domain located in southern Italy, in order to test the capabilities of the model in reproducing the main climate features of Urban Heat Islands over this area. Model evaluation has been performed in terms of 2 m temperature in an urban area and in a rural one, in order to highlight the behaviour of the parameterization in different contexts. Numerical results encourage further investigation and development of urban parameterization in very high-resolution configuration of limited area models and specifically of COSMO, to improve the representation of the maximum daily values of temperature and diurnal cycle especially in urban, but also in rural areas. Furthermore a better parameter tuning is still required for this specific test case.

Induction and Formation of Accessory Corpus Luteum after Artificial Insemination (AI) Might Increase Pregnancy Rate per AI in Heat Stressed Dairy Cows

Abstract The present study aimed to evaluate whether the induction and the formation of an accessory corpus luteum (CL) after AI might increase the pregnancy per AI (P/AI) in heat stressed dairy cows. Starting at d 50±3 post-partum, 113 lactating Holstein cows from one commercial herd during summer were scored for body condition, blood sampled and examined by ultrasound. Those bearing a CL>25mm and progesterone (P4) level>2ng/mL were synchronized using a double PGF2α injection given 12 h apart and AI-ed at detected estrus. In total 18 cows, there were not any signs of estrus (n=10) nor a P4 level <2ng/mL at the time of enrolment (n=8) and therefore they were excluded from the study, leading to 95 cows finally enrolled.. At d5 post-AI, cows were randomly allocated into 2 groups: control group (CON, n=45) without any additional treatment, and treatment group (GnRH, n=50), treated with 0.008 mg Buserelin – a GnRH agonist. Blood sampling and ultrasound examination were done at d5, d14 and at d21 after AI, whereas the pregnancy diagnosis was done at d21 and d30 after AI. Average daily temperature and relative humidity values were used to calculate the temperature-humidity index (THI). The average THI during the experiment was 79.5±0.6. At d5, no differences were observed neither between the number of the CL nor between the P4 level in both groups. At d14 and d21, 82% of the GnRH-treated cows had more than one CL versus 0% of the CON cows. Both at d14 and 21, GnRH-treated cows had higher P4 levels compared to the CON cows (p<0.05). In addition, P/AI were higher in the GnRH group than in the CON group (65% vs. 48.3%, p<0.05), whereas late embryonic losses were higher in CON in comparison to GnRH cows (10.6 vs. 4%, respectively). The BCS at the moment of insemination did not affect P/AI (p>0.05). In conclusion, the induction of an accessory CL at d 5 after AI might increase P/AI in heat stressed dairy cows.

Ambient air temperature and degree-day data analysis of the period 2006–2017 for Cyprus

Heating degree days (HDDs) and cooling degree days (CDDs) are widespread climatic indicators that depict the extremity and duration of ambient air temperature values. Over the years, they have been proven to be a useful tool for a reasonably accurate estimation of space heating and cooling requirements, as well as for the buildings’ energy performance rating and their compliance with legislative requirements. Reliable degree-days (DDs) data are a prerequisite for using the degree-day methods, so is determining the DDs values on a local and regional level, with respect to climate differentiations. The aim of this study is the calculation of HDDs and CDDs for Cyprus at various base temperatures, as such data cannot be found for Cyprus in the literature. The temperature data used were provided by the Cyprus Department of Meteorology, and these are the average daily dry-bulb ambient air temperature values as well as the daily maximum and minimum air temperature values for the period 2006–2017. Data were recorded at five meteorological stations at Paphos, Larnaca, Athalassa, Limassol and Prodromos. Monthly and annually HDDs and CDDs were calculated, for 11 base temperatures, as well as monthly and annually average temperatures for the period 2006–2017, by utilizing the DDs calculation technique of average daily temperature as proposed by ASHRAE. Additionally, an analysis of the variability and the trends of the HDDs and CDDs at the five meteorological stations during the 12-year period were performed. Finally, conclusions were drawn concerning the development of climate over the last 12 years in Cyprus.

Thermal Variability in the Lublin Region During the Frost Wave in January 2017

<p>Fale mrozów należą do ekstremalnych zjawisk pogodowych stanowiących – podobnie jak inne tego typu zjawiska – zagrożenie dla zdrowia i życia człowieka oraz wpływających niekorzystnie na środowisko przyrodnicze. Za falę mrozów przyjmuje się ciąg przynajmniej trzech kolejnych dni, podczas których minimalna dobowa temperatura powietrza była równa lub niższa od –15°C (Wibig i in. 2009). Celem niniejszej pracy jest zbadanie warunków termicznych na Lubelszczyźnie podczas szczególnie mroźnego stycznia 2017 r. Jako materiał źródłowy wykorzystano wyniki pomiarów minimalnych i maksymalnych dobowych wartości temperatury powietrza oraz terminowe wartości temperatury powietrza o kroku czasowym 1 godziny, z terenowych stacji meteorologicznych Katedry Hydrologii i Klimatologii UMCS, zlokalizowanych na obszarze Lubelszczyzny (Celejów, Leśniowice, Rybczewice, Wola Wereszczyńska, Guciów) oraz stacji meteorologicznych IMGW-PIB (Siedlce, Terespol, Lublin-Radawiec, Włodawa, Sandomierz, Zamość, Kozienice). Fala mrozów na Lubelszczyźnie wystąpiła w dniach od 5 do 11 stycznia 2017 r., przy czym na większości stacji (z wyjątkiem stacji w Terespolu) 9 stycznia minimalna dobowa temperatura powietrza była wyższa od –15°C. Podczas analizowanego okresu najniższą temperaturę powietrza zanotowano 7 stycznia na stacji w Guciowie (–25,3°C). Przyczyną tej fali mrozów był napływ powietrza arktycznego z północy.</p>

The Thermal Response of Concrete Frame Buildings in Arabic Area Considering Time-Dependent Properties of Concrete

The Arabic area is known for its significant changes in climate temperatures within different seasons. Riyadh, Cairo, Abu Dhabi, Ras Al-Khaimah, Kuwait, and Baghdad are subjected to the maximum variance in daily temperatures and presents the mean values of daily temperatures considering the data collected by the Hong Kong observatory in China for the last 30 years. The maximum mean value of daily temperature, which is 44.6 ℃ in Kuwait, and the minimum mean value of the daily temperature in Baghdad is 3.8 ℃. The maximum difference values of daily temperatures are observed in the Arabic Gulf area countries, such as Abu Dhabi, Kuwait, and Riyadh. Hence, these values will be considered in this analysis. This study results fit the thermal requirements of Arabic area and regions with similar temperature variation, accounting for various design aspects considering both methodologies of time-dependent properties of concrete as per CEB FIP 90 code and non-time dependent properties as per ACI 224.3R. For those targets a finite element method is utilized by generating 272 single- storey concrete ETABS models. The models are categorized according to column support conditions and development of concrete properties over time. The study findings are utilized to develop a clear understanding of mentioned variable's effects at thermal deformations and column reactions to aid structural engineers in the thermal design of super-long buildings with similar conditions of this study within time. The thermal displacement grows in proportion to the height of the column and the length of the slab. The findings of the analysis also show that employing thick slabs slightly decreases thermal displacements for models with hinged column supports and a 6 m column height. The thermal reactions increase in proportion to the length of the slab and the fixity conditions. Meanwhile, these reactions are inversely proportional to the height of the column. The ratios of time-dependent deformation and reaction to those of non-time-dependent properties are within the range [159%-163%] and [168%-171%] respectively. Ignoring this difference imposes defects, additional cracks, and damages at the structures and related serviceability conditions for 70 years period.

Y-shaped and fruiting wall peach orchard training system in subtropical Brazil

ASBTRACT Peach as commercial crop in Brazil is usually grown in open vase training system. However, in the 1970s large orchards changed to the Y-shaped system and higher density of plants. This system is the most used in Sao Paulo state because it allows orchard densification. However, the longevity of the trees is reduced from 15 to 8 years being the excessive exposure of internal branches to solar radiation the main reason for the reduction. Aiming to offer new alternatives of training system for peach, an experiment was carried out to evaluate the fruiting wall in comparison to Y-shaped, using the cultivar Tropic Beauty budded onto cultivar Okinawa. Ten plants by treatment were used as repetition and microclimatic equipment was installed inside the plant to measure temperature and solar radiation. Values of soluble solids (°Brix) were 9.64 to fruiting wall and 9.59 to Y-shaped, not statistically different. However most of fruit physicochemical characteristics were favorable to the fruiting wall system: fruit weight (g) – 97.56 and 90.44; pulp yield (g) – 92.42 and 85.70; pulp firmness (Kg∙cm–2) – 4.27 and 3.50; titratable acidity (g citric ac.∙100 ml–1) – 0.76 and 0.71; and ratio – 12.79 and 13.58, respectively to fruiting wall and Y-shaped. Solar radiation transmission and maximum daily temperature values for the Y-shaped were higher when compared to fruiting wall at harvest. The obtained data show that the fruiting wall training system could be an alternative to Brazilian’s growers for producing superior fruit quality without yield reduction.

An efficient surface energy–mass balance model for snow and ice

Abstract. A comprehensive understanding of the state and dynamics of the land cryosphere and associated sea level rise is not possible without taking into consideration the intrinsic timescales of the continental ice sheets. At the same time, the ice sheet mass balance is the result of seasonal variations in the meteorological conditions. Simulations of the coupled climate–ice-sheet system thus face the dilemma of skillfully resolving short-lived phenomena, while also being computationally fast enough to run over tens of thousands of years. As a possible solution, we present the BErgen Snow SImulator (BESSI), a surface energy and mass balance model that achieves computational efficiency while simulating all surface and internal fluxes of heat and mass explicitly, based on physical first principles. In its current configuration it covers most land areas of the Northern Hemisphere. Input data are daily values of surface air temperature, total precipitation, and shortwave radiation. The model is calibrated using present-day observations of Greenland firn temperature, cumulative Greenland mass changes, and monthly snow extent over the entire domain. The results of the calibrated simulations are then discussed. Finally, as a first application of the model and to illustrate its numerical efficiency, we present the results of a large ensemble of simulations to assess the model's sensitivity to variations in temperature and precipitation.

Discerning the Environmental Drivers of Annual Migrations in an Endangered Amphibian

The prevalence of studies that discern the drivers of animal migrations is increasing exponentially, in line with raised concerns over climate-driven shifts in phenological patterns. Amphibians that breed in ephemeral wetlands are particularly vulnerable owing to the stochastic nature of their breeding habitat and high survival and reproductive costs associated with untimely migrations. Knowledge of the effects of climatic cues on the timing of amphibian migration and breeding phenologies is required to understand the potential consequences of climate change and to inform conservation plans for at-risk species. Here we use six years of count data from Eglin Air Force Base, Florida, U.S., collected between 2010 and 2016, to model the phenology of migrations of Ambystoma bishopi. Models were fit with a negative binomial error distribution, with daily values of temperature and precipitation as covariates. Models were compared in an AIC framework. We found that salamander movement was strongly tied to environmental cues. A proclivity to move over a medial range of temperatures and precipitation resulted in a ‘Goldilocks’ set of conditions that facilitate migration. We also discovered a role for endogenous drivers of movement, with day of year predicting above-ground activity regardless of environmental conditions. These results contribute to our basic knowledge of the behavior of A. bishopi and provide managers with useful metrics to maximize the efficacy of conservation actions. More broadly, the methods employed within have utility to amphibian researchers to help predict the effects of climate change and tailor management strategies accordingly.

Longitudinal trends in asthma emergency department visits, pollutant and pollen levels, and weather variables in the Bronx from 2001–2008

Objective: To evaluate how asthma-related emergency department visits (AREDV), air pollutant levels, pollen counts, and weather variables changed from 2001 to 2008 in the Bronx, NY. Methods: 42,065 daily AREDV values (1 January 2001 to 31 December 2008) were collected using our institution’s Clinical Looking Glass software. Daily values of sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), temperature, and humidity were obtained from the National Climatic Data Center's Bronx station. Daily tree pollen counts were obtained from the Armonk counting station near the Bronx. Median values for each variable were analyzed using the Mann-Whitney test to compare 2001–2004 and 2005–2008 values. Simple linear regression examined associations between AREDV and individual pollutants. Due to seasonal variations of the variables, each season was considered separately. Results: There were significant decreases for AREDV, SO2, CO, and humidity for all seasons, and for NO2 in the spring and winter. Significant increases occurred for O3 in the spring, fall, and winter; for temperature in the summer and winter; and for tree pollen in the spring. Significant positive associations were found between AREDV and SO2, CO, NO2, and humidity, respectively, while significant negative associations were found between AREDV and O3 and temperature, respectively. Conclusions: From 2001 to 2008, significant: a) decreases in AREDV, SO2, CO, and humidity for all seasons, and decreases in NO2 for the spring and winter; and b) increases in O3, temperature, and spring tree pollen were observed. By tracking and anticipating environmental and pollutant changes, efforts can be made to minimize AREDV.

Research on Mechanical Performance of CRTS III Plate‐Type Ballastless Track Structure under Temperature Load Based on Probability Statistics

CRTS III (China Railway Track System III) slab ballastless track structure is one of the high‐speed railway ballastless track structures which has Chinese independent intellectual property rights. The mechanical performance of CRTS III slab ballastless track structure under temperature load has not been clear yet. Therefore, through temperature field model and temperature load values selected by statistics analysis based on long‐term meteorological data, the mechanical performance of ballastless track structure is studied under two typical working conditions with different safety probability. It is found that the daily extreme values of monthly axial uniform temperature and the daily maximum temperature gradient obey certain statistical laws. In addition, the maximum tensile stress of the self‐compacting concrete layer is located in the middle and edge of the slab bottom and the side of the slab. The maximum tensile stress of the base plate is located at the edge of the surface of the layer and the inner edge of the limiting groove. The interface normal tensile stress is located at the end and corner of the interface. Furthermore, maximum stress increases with the increase of safety probability.

Effects of extreme climatic conditions on pavement response

Conventionally it has been presumed that heavy traffic loading is the main driver that causes pavements to reach its limiting performance criteria such as fatigue and permanent deformation, and as a result, pavement designs have primarily only incorporated traffic loading. However, close monitoring of pavements has revealed that in fact, traffic loading alone may not create the conditions that lead to sudden failure of pavements. One aspect that is often not directly included in pavement design is the climatic factors, specifically temperature and moisture variations of the pavement soil. The occurrence of climatic extremes is becoming ever so frequent and there is a pressing need to better understand the effects of these extreme climatic conditions on pavement performance. This study presents the findings of an investigation into the effects of moisture and environmental conditions on the mechanical behaviour of granular pavements. The study was conducted with the aim of determining how seasonal effects from hot and wet climatic conditions impact on the sudden failure of pavements. Data was collected from state-of-the-art instrumentation on two field pavement sites located in Sunshine Coast, Australia. The sites were monitored over three years, and variations in daily temperature, moisture and strain values were analysed. Cyclic strain variations were observed in a cemented pavement basecourse layer where large fatigue tensile strains were present when moisture increased and temperature decreased. The results indicate that as moisture rises and temperature falls, critical fatigue strain increase above the fatigue endurance limit. This occurs when moisture was at or above optimum moisture content and surface layer temperature was between 38°C and 31°C. The data indicated that the change in pore pressure as a result of moisture and temperature variations within the granular basecourse soil were causing the strains in the pavement. Heavy traffic volume only had a minor effect on basecourse strain although the combined effect of soil moisture, temperature and heavy traffic loading was a cause for large fatigue strains in the pavement.

Principal components of thermal regimes in mountain river networks

Abstract. Description of thermal regimes in flowing waters is key to understanding physical processes, enhancing predictive abilities, and improving bioassessments. Spatially and temporally sparse data sets, especially in logistically challenging mountain environments, have limited studies on thermal regimes, but inexpensive sensors coupled with crowd-sourced data collection efforts provide efficient means of developing large data sets for robust analyses. Here, thermal regimes are assessed using annual monitoring records compiled from several natural resource agencies in the northwestern United States that spanned a 5-year period (2011–2015) at 226 sites across several contiguous montane river networks. Regimes were summarized with 28 metrics and principal component analysis (PCA) was used to determine those metrics which best explained thermal variation on a reduced set of orthogonal axes. Four principal components (PC) accounted for 93.4 % of the variation in the temperature metrics, with the first PC (49 % of variance) associated with metrics that represented magnitude and variability and the second PC (29 % of variance) associated with metrics representing the length and intensity of the winter season. Another variant of PCA, T-mode analysis, was applied to daily temperature values and revealed two distinct phases of spatial variability – a homogeneous phase during winter when daily temperatures at all sites were <3 ∘C and a heterogeneous phase throughout the year's remainder when variation among sites was more pronounced. Phase transitions occurred in March and November, and coincided with the abatement and onset of subzero air temperatures across the study area. S-mode PCA was conducted on the same matrix of daily temperature values after transposition and indicated that two PCs accounted for 98 % of the temporal variation among sites. The first S-mode PC was responsible for 96.7 % of that variance and correlated with air temperature variation (r=0.92), whereas the second PC accounted for 1.3 % of residual variance and was correlated with discharge (r=0.84). Thermal regimes in these mountain river networks were relatively simple and responded coherently to external forcing factors, so sparse monitoring arrays and small sets of summary metrics may be adequate for their description. PCA provided a computationally efficient means of extracting key information elements from the temperature data set used here and could be applied broadly to facilitate comparisons among more diverse stream types and develop classification schemes for thermal regimes.

Effect of climate change on thermal-ice regime of shallow lakes compared to deep lakes: Case study of lakes in the temperate zone (Northern Poland)

The objective of this study is to determine the usefulness of results of hydrological observations (1961-2015) carried out in a deep lake for the assessment changes in the ice-thermal regime of a shallow lake. The paper is based on results of daily values of surface water temperature and ice phenomena in shallow Lake Łebsko and deep Lake Charzykowskie. Similar, statistically significant, positive trends of water temperature were determined in both lakes (0.26°C 10 year-1 in Lake Łebsko and 0.25°C 10 year-1 in Lake Charzykowskie). The fastest increase in mean monthly water temperature in the analysed period (1961-2015) occurred in May (3.37°C in Lake Charzykowskie) and April (2.76°C in Lake Łebsko). The majority of elements of the thermal regime of surface waters in shallow lakes were generally determined to be similar to the same elements in deep lakes, and the effect of climatic changes on the thermal regime of both lakes was found to be similar. Less similarity is observed between elements of the ice regime, particularly in date of decline of the ice cover.