Annual and seasonal trends of cooling, heating, and industrial degree-days in coastal regions of Saudi Arabia

In this study, we systematically analyze the changing properties of reference evapotranspiration (ETref) across China using Penman?CMonteith (P-M) method, exploring the major sensitive meteorological variables for ETref, and investigating influences of human activities, mainly urbanization in this study, on ETref changes in both space and time. We obtain some important conclusions: (1) decreasing annual and seasonal ETref is observed in the east, south and northwest China. However, a long strip lying between these regions is identified to be characterized by increasing ETref; (2) in the regions east to 100°E, the net total solar radiation is the main cause behind the decreasing ETref. In northwest China, however, relative humidity is recognized as the most sensitive variable for the ETref; (3) in the east and south China, urbanization greatly influences the ETref by directly decreasing net solar radiation. The increased air pollution and aerosols in the highly urbanized regions are the main driving factors causing decreasing net radiation; and (4) this study reveals accelerating hydrological cycle from south to north China. Besides, increasing ETref in the source regions of large rivers in China may pose new challenges for the basin-scale water resource management. The results of this study highlight the integrated effects of climate changes and human activities on ETref changes in different regions of China, which will be of great scientific and practical merits in in-depth understanding of hydrological cycle alterations under the changing environment in China.     

Statistical formula to estimate heating or cooling degree-days

An expression to estimate heating or cooling degree-days accumulated on the average above or below a given temperature and for a given period of time is developed according to a statistical criterion.If the mean daily temperatures for a given month are assurned to be normally distributed the derived formula is only a function of the statistical parameters of the distribution: the normal and the standard deviation.The proposed method compares favorably with the traditional ones concerning the accuracy of the estimates and simplicity of calculations.     

Observed trends of heating and cooling degree-days in Xinjiang Province, China

The Mediterranean climate region on the west coast of the United States is characterized by wet winters and dry summers, and by high fire activity. The importance of synoptic-scale circulation patterns (ENSO, PDO, PNA) on fire-climate interactions is evident in contemporary fire data sets and in pre-Euroamerican tree-ring-based fire records. We investigated how interannual variability in two fire weather indices, the Haines index (HI) and the Energy Release Component (ERC), in the Mediterranean region of southern Oregon and northern California is related to atmospheric circulation and fire extent. Years with high and low fire weather index values corresponded to years with a high and low annual area burned, respectively. HI combines atmospheric moisture with atmospheric instability and variation in HI was more strongly associated with interannual variation in wildfire extent than ERC, which is based on moisture alone. The association between fire extent and HI was also higher for fires in southern Oregon than in northern California. In terms of synoptic-scale circulation patterns, years of high fire risk (i.e., increased potential for erratic fire behavior, represented by HI and ERC) were associated with positive winter PNA and PDO conditions, characterized by enhanced regional mid-tropospheric ridging and low atmospheric moisture. The time lag we found between fire risk potential and prior winter circulation patterns could contribute to the development of long-lead fire-climate forecasting.     

湿球温度冷度日反映制冷能耗的适用性评估

基于湿球温度提出一种新的表征制冷能耗的冷度日,利用TRNSYS软件模拟得到1961—2012年逐月制冷能耗,分析了基于湿球温度的冷度日反映我国不同建筑气候区制冷能耗的适用性。结果表明,除上海外,基于干球温度的冷度日并不能很好地反映制冷能耗,仅能解释逐月制冷能耗的17%~60%;基于湿球温度的冷度日能够很好地反映各建筑气候区的制冷能耗,可以解释逐月制冷能耗的67%~98%。此外,各建筑气候区随着设定的基础湿球温度不同,计算得到的冷度日对制冷能耗的解释量不同。基础湿球温度为16.85℃的冷度日对哈尔滨和天津制冷能耗解释量最大,而不同基础湿球温度的冷度日对上海和广州制冷能耗解释量均无明显差异。以上研究结果证实,基于湿球温度的冷度日能较好地反映各建筑气候区制冷能耗,但各气候区用湿球冷度日反映制冷能耗时应设定不同的基础湿球温度。     

Insurance against weather risk: Use of heating degree-days from non-local stations for weather derivatives

Summary ?Weather derivatives enable policy-holders to safeguard themselves against extreme weather conditions. The effectiveness and the efficiency of the risk transfer is determined by the spatial risk basis, which is the stochastic dependency of the local weather outcome being insured and the outcome of the weather underlying the insurance instrument. The lower this risk basis the higher the effectiveness and the efficiency of the risk transfer. To study the spatial risk basis component in relation to the design and evaluation of a weather derivative contract to insure for heating degree-days (HDD), the historical temperature records were analyzed for five sites across the Netherlands. Sensitivity and specificity of the insurance instrument were used to quantify the potential spatial risk basis. Setting indemnification beyond a half standard deviation above the mean meant that between 60% and 76% of the indemnable HDD were classified correctly, while 82% to 99% of the non-indemnable HDD were classified correctly. These results indicate that the spatial risk basis is a major concern and that successful weather derivatives require the utilization of carefully selected weather data obtained from meteorological stations in close proximity to the area being insured. Received November 5, 2001; revised July 3, 2002; accepted July 7, 2002     

Spatial analysis of monthly precipitation in Turkey

Summary  The principal objectives of this paper are to develop and validate an optimum interpolation method for the spatial analysis of monthly precipitation in Turkey. A two-dimensional optimum interpolation objective analysis scheme has been developed for the spatial analysis of precipitation. The model is developed for generating statistically optimum interpolation based on the irregular distribution of meteorological stations. One question that affects the optimum interpolation method and, indeed, all such techniques, is how many observations should be allowed to influence a given grid point? The method developed in this paper addresses this question. For the implementation of the method, 52 stations are considered for Turkey, with 30 years of monthly data at each point. It is observed that each monthly average spatial correlation function shows a monotonically decreasing pattern based on 15 km interval averages. The method provides high estimation accuracy in dense station locations such as in northwestern Turkey. Precipitation contour maps obtained by the optimum interpolation method indicate two spatial trends over Turkey which have not been identified in any previous study. Received June 24, 1999/Revised April 26, 2000     

Spatial and temporal drought projections of northwestern Turkey

Theoretical and Applied Climatology - Based on the meteorological data of 60 stations above the Bengbu Sluice of Huaihe River from 1961 to 2015, Crop Water Deficit Index (CWDI) and Relative...     

Spatial Heating Monthly Degree-Day Features and ClimatologicPatterns in Turkey

Summary  Degree-days as a measure of accumulated temperature deviations from a base temperature have many practical applications in various human related activities such as home cooling, heating, plant growth in agriculture and power generation in addition to energy requirement. Long temperature records are necessary for their reliable estimations at given stations. In this paper, degree-day measure has been applied to monthly temperature records for systematically changed base temperature values from − 25 °C to + 35 °C with 5 °C increments at 255 meteorology stations in Turkey. The results are represented in the form of spatial degree-day distribution maps, which are then related to various climatic, meteorological and topographic features of Turkey. For instance, free surface water bodies in forms of surrounding seas, lakes and rivers insert retardation in the expansion of heating degree-days over large regions. On the other hand, cold air penetration from polar regions in the northeastern Turkey originating from Siberia appears at moderate base temperature heating degree-days. Received August 20, 1998 Revised June 21, 1999     

Power-law Relationship in Describing Temporal and Spatial Precipitation Pattern in Turkey

Summary Wet and dry spell properties of monthly rainfall series at five meteorology stations in Turkey are examined by plotting successive wet and dry month duration versus their number of occurrences on the double-logarithmic paper. Straight line relationships on such graphs show that power-laws govern the pattern of successive persistent wet and dry monthly spells. Functional power law relationships between the number of dry and wet spells for a given monthly period are derived from the available monthly precipitation data. The probability statements for wet and dry period spells are obtained from the power law expressions. Comparison of power-law behaviours at five distinct sites in Turkey provides useful interpretation about the temporal and spatial rainfall pattern. As in temperate areas such as Turkey the rainfall amounts change mostly due to one-month-long dry or wet spells. Received August 29, 1995 Revised November 9, 1995     

Spatial variability of chilling temperature in Turkey and its effect on human comfort

Summary Air temperature, absolute humidity and wind speed are the most important meteorological parameters that affect human thermal comfort. Because of heat loss, the human body feels air temperatures different to actual temperatures. Wind speed is the most practical element for consideration in terms of human comfort. In winter, due to the strong wind speeds, the sensible temperature is generally colder than the air temperature. This uncomfortable condition can cause problems related to tourism, heating and cooling. In this study, the spatial and temporal distributions of cooling temperatures and Wind Chill Index (WCI) are analyzed for Turkey, and their effect on the human body is considered. In this paper, monthly cooling temperatures between October and March in the years 1929 to 1990 are calculated by using measured temperature and wind speed at 79 stations in Turkey. The influence of wind chill is especially observed in the regions of the Aegean, west and middle Black Sea and east and central Anatolia. The wind chill in these regions has an uncomfortable effect on the human body. Usually, the WCI value is higher in western, northern and central Anatolia than in other regions.     

Spatial and temporal patterns of trends and variability in diurnal temperature ranges of Turkey

Summary Spatial and temporal patterns of trends in the diurnal temperature ranges (DTRs) of the 70 stations and the role of maximum and minimum temperatures on the year-to-year variability and the long-term trends of the DTRs in Turkey have been investigated for the period 1929–1999. The principal results of the study are as follows:(i) The daytime maximum temperatures have shown weak warming and cooling in comparison with significant warming of the night-time minimum temperatures in many regions of Turkey and in most seasons. (ii) The DTRs have significantly decreased at most of the urbanised and rapidly urbanising stations throughout the seasons except partly in winter, without showing an apparent north/south (west–east) and land/sea gradient. (iii) Annual and seasonal DTRs of some stations have shown significant increasing trends. Nevertheless, the spatial distribution of significant increasing trends in the DTR series is geographically incoherent across the country in all seasons and annually, as compared with significantly decreased DTRs. (iv) Autumn and summer DTRs have decreased generally at a higher rate than in winter and spring. (v) Changes in the temperature regime of Turkey towards the more temperate and/or warmer climate conditions are most strongly related with the significant night-time warming in spring and summer. (vi) Magnitudes and signs of correlation coefficients and correlation patterns between the DTRs and the maximum and minimum temperatures have revealed that there is an opposite physical control mechanism on the year-to-year variability and the long-term variations and trends in the DTRs, particularly for the annual, spring and summer series. (vii) Significant increases of the night-time temperatures have most likely led to strong decreasing trends in the DTRs of most stations during the spring and summer seasons and annually and of some stations during winter and autumn. (viii) The asymmetric trends and the symmetric, but with different magnitude, trends in the maximum and minimum temperatures resulted in a significant decrease in the DTRs of many stations and are a considerable signal of ongoing changes in the climatic variability of Turkey.     

A comparison of evaporative cooling with infrared heating beneath a cirrus cloud

Data for this study were collected by the instruments mounted on the NCAR King Air and rawinsonde during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) on 19 October, 1986. The main purpose of this study is to understand the basic concept of evaporative cooling in a dry layer below a cirrus generating cell. Relative humidity with respect to liquid water RH_W and temperature lapse rate γ_e below the cirrus base at about 6.7 km were about 40% and 3.7°C km⁻¹, respectively. Evaporative cooling rate (ECR) in the 1.5 km thick subcloud layer was estimated to be approximately 0.1 to 2°C h⁻¹ and it was found to be comparable with the infrared heating rate calculated from radiation measurements. Because of ice crystal evaporation, RH_W in the same layer may reach saturation with respect to ice in 1.5 hours.     

1971-2011年辽宁寒潮时空分布特征

利用1971-2011年辽宁省58个常规观测站日最低气温资料,分析辽宁寒潮时空分布特征。结果表明：1971-2011年辽宁寒潮年平均频次空间分布存在两个大值中心,一个位于辽宁东北部地区,另一个位于辽西建平地区;11月大范围强寒潮出现最多。近41 a辽宁区域性寒潮在20世纪70年代出现最多,呈不显著的下降趋势;寒潮在10月中旬至翌年5月上旬均可出现,12月上旬至翌年2月下旬是寒潮集中出现时段,出现最多的是1月;区域性寒潮出现次数存在20、13、8a和4a的变化周期。影响辽宁区域性寒潮的主要天气形势有小槽发展型、横槽型和低槽东移型。寒潮物理量预报指标主要有：寒潮前至少有一日升温过程;500 hPa冷中心温度≤-40 ℃;地面冷高压主体中心气压为1050 hPa以上,分裂小高压中心气压为1030 hPa以上;500 hPa和850 hPa急流普遍为24 m.s-1和12 m.s-1以上;850 hPa辽宁附近等温线密集程度≥5条/10纬度;风向与等温线夹角基本大于60°。     

Concentration and gas/particle partitioning of polychlorinated biphenyls (PCBs) at an industrial site at Bursa, Turkey

Gas and particle phase concentrations of atmospheric polychlorinated biphenyls (PCBs) were measured at an urban/industrial site in the city of Bursa, Turkey. PCB concentration levels were presented between July 2004 and May 2005. Average particle and gas phase concentrations of individual PCB congeners ranged from 0.08 (PCB-183) to 6.86 (PCB-49) pg m^− 3 and from 0.01 (PCB-209) to 47.2 (PCB-33) pg m^− 3, respectively. The mean concentration of total (gas + particle) PCBs varied between 24.27 and 666.21 pg m^− 3 with an average of 287.27 ± 174.80 pg m^− 3. PCB concentrations at the sampling site were higher than the concentrations reported at non-urban sites. PCBs partitioned between gas and particle phases and the partitioning was examined according to different approaches such as logK_p–logP_L^o, logK_p–logK_OA and the Junge–Pankow model. In order to present possible interactions, a correlation matrix based on PCB congeners and meteorological parameters was constructed. Application of the Clausius–Clapeyron equation yielded a low slope value indicating possible emissions from local and regional sources originating mainly from urban/industrial areas, landfill and waste incineration plant. Then, likely dry deposition fluxes were estimated depending on reported dry deposition velocity and atmospheric concentration values.     

气候变化对天津市不同节能水平建筑制冷采暖能耗的影响

利用天津市地面气象观测站1961—2017年逐小时观测资料,通过TRNSYS软件,对不同节能水平办公建筑供热和制冷能耗,以及居住建筑供热能耗进行动态模拟,定量评估了气候变化对天津市不同节能水平建筑能耗的影响。结果表明：在供暖期和制冷期,温度均呈现显著上升的趋势,而太阳辐射则呈现下降的趋势,受其影响,1961—2017年办公和居住建筑供热能耗呈现显著下降的趋势,制冷能耗呈现微弱的上升趋势,但气候变化对供热能耗的影响要明显强于制冷能耗;随着建筑节能水平的提升,供热和制冷能耗均有一定程度的下降,其中供热能耗的降幅尤为明显,四步节能居住建筑相比于一步到三步节能居住建筑,供热能耗分别下降了53.56%、50.13%和21.25%。对新建建筑及既有建筑的节能改造,应充分考虑不同节能水平对建筑能耗的影响,结合实际需求酌情进行升级改造。除此之外,建筑节能水平的提升,会使其供热和制冷能耗变化量随温度的上升而减小,说明其对气候变化的敏感性在逐渐减弱。因此,提高建筑节能水平,可以更好的应对气候变化,保证其在未来的使用中耗能更低。     

Urban heat island and its effect on the cooling and heating demands in urban and suburban areas of Hong Kong

This study investigates the urban heat island characteristics of four major areas of Hong Kong. The areas of study include a densely populated and well-developed commercial area (i.e., Tsim Sha Tsui) and three suburban areas (i.e., Cheung Chau, Lau Fau Shan and Sha Tin) with differing degrees of development. The weather station data of respective areas were acquired from the Hong Kong Observatory. The urban heat island intensity, determined as the air-temperature difference between the selected urban/suburban area and the reference rural area (i.e., Ta Kuw Ling) with thin population and lush vegetation, was used for the analysis. Results showed stronger heat island effect during winter and nighttime than during summer and daytime. An investigation of the cooling and heating degree days indicate that all areas have observed higher number of cooling degree days. However, the cooling degree days were the maximum while heating degree days were the minimum in the urban area (i.e., Tsim Sha Tsui). Clearly, the minimum heating degree days and the maximum cooling degree days in the urban area were a direct consequence of urban heat island. The 10-year (i.e., from 1995 to 2005) average shows that Cheung Chau experienced the least number of cooling degree days while Lau Fau Shan experienced the highest number of heating degree days. Seemingly, the area of Cheung Chau offers better thermal comfort conditions with the minimum number of cooling and heating degree days.     

1960—2015年中国冬半年极端降温过程事件的时空演变特征

利用1960-2015年中国2 474个站点的逐日最低气温资料,采用REOF方法将中国分为7个区域,通过对每个区域内所有站点降温阈值进行平均,得到了7个降温阈值。当某区域内测站单日降温幅度超过区域平均阈值时,认为该测站发生一次极端降温事件。7个区域降温平均阈值各异,总体呈北大南小特征,最大降温-10.6℃,最小-7.6℃。根据上述定义,研究了中国冬半年极端降温过程事件的时空演变特征。结果表明：极端降温事件发生频数呈北多南少的空间分布。北部地区存在多个频发中心,在42°N和35°N附近存在两个高频发生带。南部地区频数呈一定的带状分布,在25°N附近发生该事件的频率亦高于南部其他地区。近56 a来,极端降温事件频数变化总体呈减少趋势,前期较明显,中后期趋于稳定。各年代频数的空间分布基本一致,但前期总体表现为北部增多。而在1990s则转变为南负北正的空间分布,后期中部及沿海地区发生了趋势符号的年代际改变。进一步分析表明,各区域极端降温频数突变的年份均不一致且突变前后的频数存在较大差异。这些结果可为深刻认识极端低温事件的变化规律和气候预测提供线索。     

气候变化对中国华北地区办公建筑供热制冷能耗的影响评估

以中国华北地区五大城市办公建筑为例,利用1961—2017年气象数据和TRNSYS软件模拟的供热制冷负荷数据,评估了气候变化背景下华北地区建筑供热制冷负荷的变化。在此基础上,对模拟负荷和气象要素进行多元线性逐步回归分析,揭示了影响建筑供热、制冷负荷的主要气象因子。结果表明：1961—2017年中国华北五大城市供热负荷均呈下降趋势,降幅为0.05（石家庄）—0.13 kWh·m^-2·（10 a）^-1（呼和浩特）;各城市制冷负荷的变化不同,仅呼和浩特为增多,增幅为0.04 kWh·m^-2·（10 a）^-1,其余城市制冷负荷无明显变化;从总负荷来看,各城市均呈下降趋势,降幅为0.05（太原）—0.10 kWh·m^-2·（10 a）^-1（呼和浩特）。由供热制冷负荷与气象要素的回归分析可知,冬季供热负荷主要受气温影响,五大城市的显著增温导致供热负荷减少;与此不同,夏季制冷负荷主要受气温、太阳辐射的共同影响,呼和浩特平均气温和太阳辐射均呈显著上升趋势,导致其制冷负荷显著增加。其他城市气温显著升高,而太阳辐射显著降低,二者的综合作用导致制冷负荷没有明显的变化趋势。总体来看,在气候变暖背景下,中国华北地区冬季供热负荷明显降低,而夏季制冷负荷并未明显增加,导致总负荷显著降低,气候变暖总体上对建筑节能有利。