Daily Minimum Air Temperature Research Articles

Tendências de temperaturas mínimas e máximas do ar no Estado de Minas Gerais

O objetivo deste trabalho foi avaliar tendências das temperaturas mínimas e máximas no Estado de Minas Gerais. Foram avaliados dados de 43 municípios, tendo-se considerado as escalas anual e sazonal - janeiro, abril, julho e outubro, que representam os meses centrais de verão, outono, inverno e primavera, respectivamente. Séries históricas de temperaturas mínimas e máximas do ar diárias, com extensão mínima de 30 anos, foram analisadas com base no teste de Mann-Kendall e no uso de regressão linear simples. As tendências foram consideradas significativas somente quando ambas as avaliações foram significativas; neste caso, determinaram-se as taxas de alteração das temperaturas. Houve boa concordância entre os testes de significância para a detecção de tendências nas séries históricas, na maioria dos municípios. Observou-se tendência de elevação das temperaturas mínimas em julho de até 1,5ºC por década, com tendências generalizadas de aumento na maior parte do estado, em outubro e janeiro, e também na escala anual. Exceções foram verificadas especialmente em municípios de maiores altitudes, em que as temperaturas mínimas diminuíram no inverno. Há predominância de municípios com tendência significativa de aumento de temperaturas, independentemente da escala de avaliação. Tendências de aumento nas temperaturas são esperadas mais comumente no sentido sul-norte do Estado de Minas Gerais.

Multiple crossings of a large glacial river by Canada Lynx (<em>Lynx canadensis</em>)

Rivers may act as barriers to the movement of terrestrial mammals, which could limit dispersal and gene flow. Glacial rivers are particularly hazardous because of the cold water temperature and swift current. Yet, we determined that 2 Canada Lynx (Lynx canadensis) equipped with GPS collars repeatedly swam across the main channel of the Tanana River in interior Alaska in 2011 as late in the season as November, when the average minimum daily air temperature was −27°C. These observations are consistent with the low level of genetic structure observed in Canada Lynx in northwestern North America and suggest that even large rivers may pose less of a barrier to movement by Canada Lynx than expected.

Analyses of trends in air temperature in the United Kingdom using gridded data series from 1910 to 2011

AbstractGridded temperature datasets covering the UK at 5 km × 5 km resolution have been analysed for temporal and spatial patterns of change and variability. Decadal‐scale variability is visualized by smoothing the data series using a kernel smoother. Trends have been analysed by comparing averages for a baseline period with averages for a recent period, as well as using linear regression. Spatial patterns of change have been mapped by calculating trends for each grid point.Monthly gridded datasets of daily maximum, minimum and mean air temperatures are available from 1910 to date. These show statistically significant increases for all parts of the UK, with the rate of change increasing from the north and west to the south and east. Seasonally, the least significant changes have occurred in the winter, with significant increases for most districts for all of the other seasons.Derived indices based on daily temperature are available from 1961 onwards. There have been significant decreases in heating degree days and increases in growing degree days for all districts, while changes in cooling degree days are less significant as the values are low and inter‐annual variability dominates. There have been significant decreases in frost days, especially in spring and autumn, and this is linked to significant increases in growing season length, especially for Scotland.

Variability of temperature extremes in the Yellow River basin during 1961–2011

The variability of temperature extremes was widely discussed in the past few decades worldwide associated with global warming, which impacted the hydrological cycle and energy balance. In this study, on the basis of daily maximum and minimum air temperature at 62 meteorological stations in the Yellow River basin, the changes in 13 indices of temperature extremes recommended by the ETCCDI were investigated in the Yellow River basin from 1961 to 2011. Both cold extremes and warm extremes showed a warming trend, with a large proportion of stations having statistically significant trends for most temperature indices. Because of a faster increase in minimum temperature than maximum temperature, diurnal temperature range (DTR) has decreased by −0.07 C°/decade. For cold extremes indices, i.e. coldest night (TNn), coldest day (TXn), cool nights (TN10p), cool days (TX10p), frost day (FD) and icing day (ID), the trends during the period of 1961–2011 were 0.23 and 0.22 C°/decade, and −5.23, −3.31, −2.61 and −3.16 days/decade, respectively. For warm extremes, i.e. warmest night (TNx), warmest day (TXx), warm nights (TN90p), warm days (TX90p), warm spell duration index (WSDI) and growing season length (GSL), the trends were 0.20 and 0.21 C°/decade, and 3.80, 3.26, 2.93 and 4.81 days/decade, respectively. In general, the indices have the largest change magnitudes in the arid and semi-arid sub-regions, followed by the high-elevation sub-region, and the indices have the smallest changes in the eastern monsoon sub-region. Relationships between the changes in the temperature extremes and the changes in the large-scale atmospheric circulations were studied. Results show that the changes in the temperature extremes were consistent with the changes in the area and strength of Northern Hemisphere Subtropical High (NHSH) and Northern Hemisphere Polar Vortex (NHPV).

New combined models for estimating daily global solar radiation from measured air temperature in semi-arid climates: Application in Ghardaïa, Algeria

In this paper, combined empirical models and a Bayesian neural network (BNN) model have been developed to estimate daily global solar radiation (GSR) on a horizontal surface in Ghardaïa, Algeria. An experimental database of daily GSR, maximum and minimum air temperatures of the year 2006 has been used to estimate the coefficients of the empirical models, as well as to train the BNN model. Six months of the year 2007 (summer period: May, June, July, and winter period: October, November, December) have been used to test the calibrated models, while six months of the year 2012 (from 1st February to 31th July) have been used to check generalisation capability of the developed models as well as the BNN model. Results indicate that the new calibrated models are able to estimate the global solar radiation with an excellent accuracy in this location. Calibrated models are also compared with the developed BNN model to show their effectiveness.

Future climate change impacts on the ecohydrology of Guishui River Basin, China

Quantifying the impacts of future climate change on the ecosystem and hydrology is very important to ecohydrology research. In this paper, the vegetation model BIOME BioGeochemicalCycles (BIOME-BGC) and the Hydrological Simulation Program-FORTRAN (HSPF) are combined to investigate the potential impact of climate change on the hydrology and ecosystems of the Guishui River Basin in Beijing China, under two emission scenarios A2 and B2 of the future period 2010–2099. The projected daily maximum and minimum air temperatures, precipitation and evapotranspiration (ET) of HadCM3 are downscaled on to local meteorological stations using the SDSM (Statistical Downscaling Model). The model calibration and validation results are in accord with observed data of surface runoff and Net Primary Productivity (NPP). Average climate projections based on two emission scenarios were used in simulations to assess future ecohydrological responses in the Guishui River basin. Also, the uncertainties in climate change impacts are discussed in detail. The predicted daily maximum and minimum air temperatures and evapotranspiration show a reasonable upward trend, while daily precipitation and surface runoff generally show a downward trend in the next 90 years. The changing rates of daily maximum and minimum temperatures, precipitation, evapotranspiration and surface runoff are 0.46°C, 0.45°C, −3.68mm/year, 15.83mm/year and −0.05m3/s (0.26°C, 0.26°C, −4.99mm/year, 9.36mm/year and −0.04m3/s) per decade under A2(B2) scenarios, respectively. The results also show that global warming impacts would decrease annual discharge and increase annual NPP (at the rate of 10–30%). These results present a serious challenge for water and land management in the basin and will provide support for regional water management.

Comparison of heat-unit methods to predict tomato anthesis

The aim of this work was to compare methods to predict the time of anthesis in tomato (Solanum lycopersicum L.). Two independent experiments were carried out using seeds of the Tauro commercial hybrid. Daily maximum and minimum air temperatures were measured by means of an electronic thermometer with data storage; the photoperiod was calculated using a mathematical procedure. The moment at which each inflorescence presented 50% of its flowers in anthesis was recorded. The use of calendar days (CD) had a high dispersion, which was measured with a variation coefficient (VC) higher than 3.70% for all inflorescences. The method that considered both a base temperature and the photoperiod allowed the highest prediction uniformity for the conditions of this assay, since its VC was lower than 0.30%.

Evaluation of the temporal relationship between daily min/max air and land surface temperature

Daily minimum and maximum air temperature (min/max Ta) exhibits a strong linear correlation with remotely sensed land surface temperature (LST). However, LST-based predictions of min/max Ta exhibit a strong seasonal pattern in their errors. This study examines the temporal trends in min/max Ta and LST, and shows that the strongest correlation exhibited by any of these variables is a temporal autocorrelation that is periodic in nature. This study analyses the temporal relationship between min/max Ta and LST, and shows that this results in a temporal trend in the errors of LST-based min/max Ta predictions that can primarily be explained by a phase shift between the seasonal oscillations of min/max Ta and LST. After removing the elevation and periodic temporal trend from the min/max Ta and LST measurements, a weak linear correlation was exhibited between min Ta and LST and a moderate linear correlation was exhibited between max Ta and LST. Fitting models to the detrended min/max Ta and LST measurements resulted in an LST-based model of min/max Ta that no longer exhibited seasonal variability in the model errors, and had a lower mean absolute error (MAE) than either a model based only on the elevation and temporal trends or one based on the elevation and LST trends alone. Thus, the results of this study show that in creating relationships between LST and air temperature, it is important to address the phase shift between the annual oscillations of these variables. This study shows that removing the annual oscillation using a Fourier model of the temporal trend improves the LST-based min/max Ta prediction by 0.6°C to 0.8°C.

Estimation of the Global Solar Radiation on the Horizontal Surface from Temperature Data for the Vhembe District in the Limpopo Province of South Africa

The lack of grid lines in the remote rural areas of South Africa necessitates the use of the solar energy as an alternative energy resource. Solar radiation at a given location is one of the primary factors considered for the installation of renewable energy devices. In some developing countries, the estimation of solar radiation becomes a challenge due to the unavailability of limited weather data. One of the options to solve this problem is the use of the mean daily maximum and minimum air temperatures to estimate the global solar radiation of a particular area, so that the designer and the installer of the renewable energy systems can estimate the energy that can be harnessed in those areas and make decisions on the suitability of the technology to be installed. In the present study, an attempt has been made to estimate the global solar radiation from the observed mean daily maximum and minimum air temperatures for some selected stations in the Vhembe District of the Limpopo Province in South Africa and to test the validity of the theoretical equation by Hargreaves and Samani. The computed values are compared with the weather station data. The value of the empirical coefficient Kr is also calculated and compared with the literature values. The yearly average value of Kr for each station was calculated and a value of 0.16 was obtained, which is equal to the value reported on the literature. A reasonable agreement between the estimated and observed solar radiation values suggests that this equation can be used to estimate a set of radiation data for this region.

Risk occurrences of damaging frosts during the growing season of vegetables in the Elbe River lowland, the Czech Republic

This study has, for the first time, analysed in detail the risk occurrences of the last spring frost, first fall frost and the length of the frost-free period during the growing season of vegetable crops at a high horizontal resolution of 10 km in the Elbe River lowland in the Czech Republic. The daily minimum air temperature from 116 grid points throughout the studied area for the period 1961–2011 was used. The daily values of minimum air temperature ranges of 0 to −1.1 °C, −1.2 to −2.2 °C and below −2.2 °C were considered to constitute mild, moderate and severe frost intensities, respectively. Firstly, the spatiotemporal variability of the date of the last spring frost, the date of the first fall frost and the length of the frost-free period in the Elbe River lowland is provided. Secondly, the estimation of the probability of a later date in the spring and an earlier date in the fall for various severe frost events and the length of the frost-free period is determined. Third, the changes in the timing of the last and first frosts of the three severities, as well as the length of the frost-free period, are evaluated. From 1961 to 2011, the Elbe River lowland has experienced a decrease in the number of frost days, while the length of the frost-free period between the last spring frost and the first fall frost has increased. The temporal evolution of the frost-free period anomalies displays two distinct periods: a shortening of the frost-free period in the 1960s and an intensified lengthening of the frost-free period since the 1980s. Whereas the latest spring frost has ended on an earlier date across the Elbe River lowland, the first frost date in the fall has generally been delayed to a later date. The dates of the last spring frost have advanced by −0.21 days per year on average. The fall dates are delayed up to 0.18 days per year, whereas the frost-free period is lengthening by up to 0.39 days per year on average. However, regional frost series suggests that the frost-free period exhibits a large amount of inter-annual variability. In terms of the growth of field vegetables, a late spring frost remains a risk factor, but the degree of risk has decreased. There is a 25 % chance of the occurrence of dangerous spring frosts during the planting of field vegetables after 3rd May, but after 15th May, the risk is only 10 %.

Can temperature extremes in China be calculated from reanalysis?

Based on daily maximum, minimum and mean surface air temperature from National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis (NCEP/NCAR) and European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses, the distributions of twenty temperature indices are examined in China during 1958–2011. ECMWF includes ERA-40 for the period 1958–2001 and ERA-Interim during 2002–2011. The consistency and discrepancy of extreme indices between reanalyses and observations (303 stations) are assessed. In most cases, temperature indices between NCEP/NCAR and ECMWF have good agreements. For both reanalysis, cold days/nights have decreased, while warm days/nights have increased since 1980. Temperatures of the coldest days/nights and warmest days/nights significantly increase over the entire China, and the diurnal temperature range demonstrates slight variations; the amounts of growing season length, and summer/tropical days have increased, consistent with the decrease in numbers of frost/ice days. Furthermore, the persistence of heat wave duration and warm spell days has increased and consecutive frost days have reduced. Meanwhile, consecutive frost days, cold wave duration and cold spell days from NCEP/NCAR have decreased and consecutive frost days have increased, while these indices from ECMWF turn to the opposite directions. Compared with observations, temperature extremes from two reanalyses have small relative bias and the root mean squared errors, while correlation coefficients are positively high. These suggest that both reanalyses can reproduce the variability of temperature extremes obtained from observations, and can be applied to investigate climate extremes to some extent, although the biases exist due to the assimilation differences.

Effects of air temperature and humidity on average daily gain in feedlot cattle of different genotypes

Abstract. The purpose of this study was to observe Holstein, Brown Swiss, Simmental and cross breed Anatolian Black genotypes fattened in feedlot regarding their ability to tolerate temperature and humidity and to compare Temperature Humidity Index types under climatic conditions of Şanlıurfa province in Turkey. Data obtained from a commercial farm composed of 70 594 test day records of 11 117 cattle (6 513 Holstein, 3 546 Brown Swiss, 838 Simmental and 220 Anatolian Black Crosses). Meteorological data were provided from nearest weather station located 9.04 km away from feedlot area. THI values were calculated by using daily maximum, minimum and average air temperature and, humidity values according to three different combinations for each animal. Analysis were based on such a model that includes effects of year, sex, age, season, days on feed, beginning stage of fattening and several types of THI. Results showed that, Simmental and Anatolian Black genotypes were slightly more tolerant to heat stress compared to Holstein and Brown Swiss. In addition, Anatolian Black genotype was more sensitive to cold stress when compared to other genotypes. Different breakpoint values for stress and comfort zone intervals were obtained when different combinations of temperature and humidity variable (maximum or minimum) were used in THI formula.

A three-year increase in soil temperature and atmospheric N deposition has minor effects on the xylogenesis of mature balsam fir

Tree growth in most boreal forests is strongly regulated by temperature and nitrogen (N) availability. The expected increases in soil temperature and N deposition over the next decades have the potential to affect the phenology of tree growth and xylogenesis. To test for these changes on xylogenesis of balsam fir (Abies balsamea (L.) Mill), 12 mature trees were subjected to a combination of experimentally increased soil temperature (+4 °C) with an earlier snowmelt (2–3 weeks) and N deposition (3 × ambient rain N concentrations using NH4–NO3 in artificial precipitation) over a 3-year period. Increased soil temperature and atmospheric N deposition had no significant effect on the number of tracheids produced (38–51), tracheid diameter (27.2–29.0 μm) and cell wall thickness (2.5–3.1 μm). For the 3 years of treatment, xylogenesis was initiated at minimum and average daily air temperatures of 0.6 ± 0.5 and 6.5 ± 0.6 °C, respectively, with inter-annual differences of 17 days in the onset of xylogenesis. The earlier snowmelt induced by soil warming did not hasten resumption of xylogenesis, and the time dynamics of xylogenesis was not affected by higher N deposition. Our results suggest that soil temperature and the timing of snowmelt have no direct influence on the breaking of cambium dormancy in balsam fir. The short-term effects of increased soil temperature and N deposition on xylogenesis of mature balsam fir appear to be small compared with the effects of air temperature and are likely to be associated with a persistent N limitation.

Effects of climate variability and climate change on crop production in southern Mali

In West Africa predictions of future changes in climate and especially rainfall are highly uncertain, and up to now no long-term analyses are available of the effects of climate on crop production. This study analyses long-term trends in climate variability at N’Tarla and Sikasso in southern Mali using a weather dataset from 1965 to 2005. Climatic variables and crop productivity were analysed using data from an experiment conducted from 1965 to 1993 at N’Tarla and from a crop yield database from ten cotton growing districts of southern Mali. Minimum daily air temperature increased on average by 0.05°C per year during the period from 1965 to 2005 while maximum daily air temperature remained constant. Seasonal rainfall showed large inter-annual variability with no significant change over the 1965–2005 period. However, the total number of dry days within the growing season increased significantly at N’Tarla, indicating a change in rainfall distribution. Yields of cotton, sorghum and groundnut at the N’Tarla experiment varied (30%) without any clear trend over the years. There was a negative effect of maximum temperature, number of dry days and total seasonal rainfall on cotton yield. The variation in cotton yields was related to the rainfall distribution within the rainfall season, with dry spells and seasonal dry days being key determinants of crop yield. In the driest districts, maize yields were positively correlated with rainfall. Our study shows that cotton production in southern Mali is affected by climate change, in particular through changes in the rainfall distribution.

Adjustment of radiation use efficiency of winter wheat by air temperature at different irrigation regimes and nitrogen rates

In this research, radiation use efficiency (RUE) of winter wheat was determined under different irrigation regimes and nitrogen application rates in experimental field at southwest Iran (semi-arid region) in 2009–2010 and 2010–2011. The experiment was laid out as a split plot design, with irrigation treatments as main plots and N fertilization as sub-plots with three replications. Irrigation treatments were 1.2 (I4), 1.0 (I3), 0.8 (I2), and 0.5 (I1) times of the full irrigation requirements and N treatments were 0 (N1), 46 (N2), 92 (N3), and 136 (N4) kg ha−1. Air temperature had significant effects on RUE that was adjusted by multiplication of hourly temperature factor to the hourly values of solar radiation (RUE a ). The values of RUE a were significantly different from the values of RUE in both growing seasons. The values of RUE a ranged from 1.44 to 1.83 g MJ−1 and 1.45 to 1.81 g MJ−1 in 2009–2010 and 2010–2011, respectively. In both growing seasons, minimum and maximum values of RUE were at I1N1 and I4N4 treatments, respectively. The methods of daily maximum and minimum air temperature were modified for considering the effects of air temperature on RUE at locations where hourly air temperature and radiation were not available.

Quantifying the Non-Gaussianity of Wintertime Daily Maximum and Minimum Temperatures in the Southeast

Abstract In this paper the statistics of daily maximum and minimum surface air temperature at weather stations in the southeast United States are examined as a function of the El Niño–Southern Oscillation (ENSO) and Arctic Oscillation (AO) phase. A limited number of studies address how the ENSO and/or AO affect U.S. daily—as opposed to monthly or seasonal—temperature averages. The details of the effect of the ENSO or AO on the higher-order statistics for wintertime daily minimum and maximum temperatures have not been clearly documented. Quality-controlled daily observations collected from 1960 to 2009 from 272 National Weather Service Cooperative Observing Network stations throughout Florida, Georgia, Alabama, and South and North Carolina are used to calculate the first four statistical moments of minimum and maximum daily temperature distributions. It is found that, over the U.S. Southeast, winter minimum temperatures have higher variability than maximum temperatures and La Niña winters have greater variability of both minimum and maximum temperatures. With the exception of the Florida peninsula, minimum temperatures are positively skewed, while maximum temperatures are negatively skewed. Stations in peninsular Florida exhibit negative skewness for both maximum and minimum temperatures. During the relatively warmer winters associated with either a La Niña or AO+, negative skewnesses are exacerbated and positive skewnesses are reduced. To a lesser extent, the converse is true of the El Niño and AO−. The ENSO and AO are also shown to have a statistically significant effect on the change in kurtosis of daily maximum and minimum temperatures throughout the domain.

气候变化对渭河流域径流的影响

本文采用GCMs和水文模型耦合的方式，基于SWAT在渭河流域构建分布式水文模型，并采用SUFI-2算法进行参数敏感性分析、参数率定、模型验证以及不确定性分析，从而对渭河流域1961~2008年的径流过程进行模拟。然后将GCMs降尺度生成不同情景下降水、最高、最低气温日序列输入SWAT模型，模拟流域未来径流量，从而分析未来不同气候变化条件下流域径流可能的变化。研究结果表明：2046~2065和2081~2100时期不同情景下流域多年平均径流量分别为80.4与104.3亿m3，较基准期增加12.4%和45%。未来两个时期，枯季流量较基准期更低，而洪峰流量则将较基准期更高，即流域内极端事件(干旱与洪水)在未来两个时期有加剧趋势。不同情景下渭河流域径流深空间变化较为一致，即上游部分子流域和北洛河上游地区径流量较基准期有所减少，而流域中下游地区径流量均呈一定的增加趋势。 In this study, Soil and Water Assessment Tool (SWAT) was selected to set up a hydrological model in the Wei River basin (WRB), calibrated and validated with Sequential Uncertainty Fitting program (SUFI-2) based on river discharge, then future daily precipitation, maximum and minimum air temperature data series at each station, generated by the Statistical Downscaling Method (SDSM), were inputted to drive the SWAT model for analyzing the spatiotemporal characteristics of runoff during the future periods (2046-2065 and 2081-2100) under three climate scenarios including CSIRO, INM and MRI. Two emission scenarios (SRES A2 and SRES B1) were also included. The results show that average values of mean annual runoff in the periods of 2046-2065 and 2081-2100 were 80.4 × 108 m3 and 104.3 × 108 m3, which were greater than runoff in the base period by 12.4% and 45%, respectively. In both of the future periods, low flows would be much lower, while high flows tend to be much higher than that in the base period. In other words, there would be more extreme events (droughts and floods) in the future. For the spatial distribution of runoff over the WRB, it showed consistency for runoff changes under most combined scenarios, with runoff decreased at some areas of upstream and the upstream of Beiluo River, while increased at mid-lower stream of the WRB.

Changes in daily climate extremes in Xinjiang, northwestern China

Based on daily maximum and minimum surface air temperature and precipitation records at 48 meteorological stations in Xinjiang, the spatial and temporal distributions of climate extreme indices have been analyzed during 1961-2008. Twelve temperature extreme indices and six precipitation extreme indices are studied. Temperature extremes are highly correlated to annual mean temperature, which appears to be significantly increasing by 0.08 °C per year, indicating that changes in temperature extremes reflect consistent warming. The warming tendency is clearer at stations in northern Xinjiang as reflected by mean temperature. The frequencies of cold days and nights have both decreased, respectively by 0.86 and 2.45 d/decade, but the frequencies of warm days and nights have both increased, respectively by +1.62 and +4.85 d/decade. Over the same period, the number of frost days shows a statistically significant decreasing trend of 2.54 d/decade. The growing season length and the number of summer days exhibit significant increasing trends at rates of +2.62 and +2.86 d/decade, respectively. The diurnal temperature range has decreased by 0.28 °C/decade. Both annual extreme low and high temperatures exhibit significant increasing trend, with the former clearly larger than the latter. For precipitation indices, regional annual total precipitation shows an increasing trend and most other precipitation indices are strongly correlated with annual total precipitation. Average wet day precipitation, maximum 1-day and 5-day precipitation, and heavy precipitation days show increasing trends, but only the last is statistically significant. A decreasing trend is found for consecutive dry days. For all precipitation indices, stations in northwestern Xinjiang have the largest positive trend magnitudes, while stations in northern Xinjiang have the largest negative magnitudes.更多还原

Solar radiation estimated from measured air temperature: a review and proposed a new model

Estimation of solar radiation from measured air temperature offers an important alternative in the absence of measured solar radiation because of the wide availability of air temperature data. Solar radiation is considered as the most important parameter in meteorology, solar conversion, and renewable energy applications. Many correlation models have been developed to estimate daily solar radiation using air temperature measurement. The main objective of this paper is to present an overview of methods based on air temperature data to predict solar radiation data. Published literature presented in this paper show the importance of air temperature data as a design tool for the simulation of solar radiation data. The models presented in this paper provide good estimation of solar radiation data, especially in isolated areas, where the weather data are not always available. Also, we propose one new model for estimating daily global solar radiation from measured air temperature for Madinah site. A newly developed model that includes the difference between maximum and minimum daily air temperature estimates the global solar radiation with higher accurately.

1월 일최저기온 평균을 이용한 한국의 재현기간별 일 최저기온 극값 예측

이 연구는 1월 일 최저기온의 평균을 이용하여 재현기간별 일 최저기온의 극값을 예측하는 방법을 개발하기 위해서 수행되었다. 전국 61개 기상관서의 1961~2010년의 50년 간의 일 최저기온자료를 이용하여 전체 연구를 수행하였다. 1월의 일 최저기온의 분포는 대부분 정규분포를 나타내고 있어, 이는 평균과 표준편차로부터 일 최저기온을 확률적인 기댓값으로 예측될 수 있었다. 이를 위하여 일 최저기온평균으로부터 일 최저기온의 표준편차의 변이를 추정하는 2차식을 개발하였다. 과거 10, 20, 30, 40, 50년의 재현 기간별로 관측된 일 최저기온의 평균, 표준편차, 극값을 분석하여 재현기간별 극값을 예측할 수 있는 계수를 도입하였고, 이 계수를 재현기간별로 추정할 수 있는 로그함수식도 개발하였다. 이 방법을 이용하여 과거 두 기간의 30년 자료를 이용하여 61개 지점에 대해 검증하였는데 평균 <TEX>$1.1^{\circ}C$</TEX>, 최대 <TEX>$5.3^{\circ}C$</TEX>의 오차를 가지고 과거 30년 재현기간의 일 최저기온의 극값을 예측할 수 있었다. This study was conducted to develop a practical method for estimating the extremes of minimum air temperature with given return-period based on the frequency distribution of daily minimum air temperature in January. Daily temperature data were collected from 61 meteorological observatories country-wide from 1961 to 2010. Most of daily minimum temperature in January could be represented by a normal-distribution, so it is possible to predict stochastically the lowest temperature by the mean and standard deviation. We developed a quadratic function to estimate standard deviation in terms of daily minimum temperature in January. Also, we introduced a coefficient which can be used to predict an extreme of minimum temperature with mean and standard deviation, and is dependent on return-periods. Using this method, we were able to reproduce the past 30-year extremes with an error of 1.1 on average and 5.3 in the worst case.