Characterizing the urban temperature trend using seasonal unit root analysis: Hong Kong from 1970 to 2015

This paper explores urban temperature in Hong Kong using long-term time series. In particular, the characterization of the urban temperature trend was investigated using the seasonal unit root analysis of monthly mean air temperature data over the period January 1970 to December 2013. The seasonal unit root test makes it possible to determine the stochastic trend of monthly temperatures using an autoregressive model. The test results showed that mean air temperature has increased by0.169?C(10 yr)~(-1)over the past four decades. The model of monthly temperature obtained from the seasonal unit root analysis was able to explain 95.9% of the variance in the measured monthly data — much higher than the variance explained by the ordinary least-squares model using annual mean air temperature data and other studies alike. The model accurately predicted monthly mean air temperatures between January 2014 and December 2015 with a root-mean-square percentage error of 4.2%.The correlation between the predicted and the measured monthly mean air temperatures was 0.989. By analyzing the monthly air temperatures recorded at an urban site and a rural site, it was found that the urban heat island effect led to the urban site being on average 0.865?C warmer than the rural site over the past two decades. Besides, the results of correlation analysis showed that the increase in annual mean air temperature was significantly associated with the increase in population, gross domestic product, urban land use, and energy use, with the R~2 values ranging from 0.37 to 0.43.     

1881—2010年哈尔滨市气候变化及其影响

利用哈尔滨站1881—2010年的月平均气温、1909—2010年的月总降水量和1961—2010年哈尔滨所辖区、县（市）月平均气温、月总降水量资料,采用线性趋势分析方法,计算了哈尔滨市气温、降水变化速率,分析了哈尔滨市气候变化特征;阐述了气候变化对哈尔滨市的影响。结果表明：近50 a,除巴彦7月气温略呈下降趋势外,哈尔滨市各区、县（市）各月、季、年平均气温均呈升高趋势。哈尔滨各区、县（市）各月、季、年总降水量变化趋势不一致。近130 a,哈尔滨市年、季平均气温均呈明显的上升趋势,20世纪80年代开始明显增温,21世纪开始增温尤为显著。近百年来,哈尔滨市年、季总降水量均呈减少趋势。气候变化对哈尔滨市农业、能源等方面的影响有利有弊,但对于水资源、人体健康和交通等有较大的负面影响。     

Climatic features of the Belaya River runoff formation

Spatiotemporal regularities of changes in mean annual air temperature and annual precipitation amount values for the Belaya River basin were revealed on the basis of the analysis of statistical homogeneity of their long-term series. It is established that warming has occurred by now and the increase in precipitation amount is registered in the Belaya River basin. Revealed was the contribution of mean seasonal air temperature and precipitation changes to the changes in their mean long-term values.     

中国近50a气候变化复杂性分析

分析了我国气温和降水量变化的兰帕尔－齐夫复杂度空间分布特征，结果表明，平均而言，我国平均气温和降水量变化的复杂度约为10－11，小于随机序列的复杂度13，年平衡气温变化序列的复杂度最小，秋季平均气温变化序列的复杂度最大，季节和年平均气温序列的复杂度小于月平均气温变化序列的复杂度，月总降水量变化序列的复杂度为西部，北部大于南部和东部，我国东南沿海地区气候要素变化的复杂度最大。     

1881-2010年哈尔滨市气候变化及其影响

利用哈尔滨本站1881-2010年的月平均气温、1909-2010年的月总降水量和1961-2010年哈尔滨所辖区、县（市）月平均气温、月总降水量资料,采用线性趋势分析方法,计算了哈尔滨市气温、降水变化速率,分析了哈尔滨市气候变化特征;阐述了气候变化对哈尔滨市的影响。结果表明：近50a,除巴彦7月气温略呈下降趋势外,哈尔滨各区、县（市）各月、季、年平均气温均呈升高趋势。哈尔滨各区、县（市）各月、季、年总降水量变化趋势不一致。近130a,哈尔滨市年、季平均气温均呈明显的上升趋势,20世纪80年代开始明显增温,21世纪开始增温尤为显著。近百年来,哈尔滨市年、季总降水量均呈减少趋势。气候变化对哈尔滨市农业、能源等方面的影响有利有弊,但对于水资源、人体健康和交通等方面有较大的负面影响。     

Creation of high-resolution climatic grid datasets for the territory of Georgia

Created are the grid datasets of monthly mean and annual mean temperature as well of monthly, seasonal, and annual values of the total precipitation with the resolution of 25 km for the period of 1936–2011. The obtained datasets characterize the real picture of the spatial distribution of temperature and precipitation on the territory of Georgia; therefore, they are used for working out geoinformative maps of temperature and precipitation variations. Revealed are the areas and centers with different intensity of warming and cooling. It is found that the annual temperature and total annual precipitation averaged for the territory do not vary considerably under conditions of the global warming.     

Precipitation effects on aerosol concentration in the atmospheric surface layer

The effects of wintertime and summertime precipitation on the mean (semiannual, seasonal, and monthly) concentration of aerosol particles of different sizes in the atmospheric surface layer are analyzed on the basis of the data of 15-year measurements of atmospheric aerosol in the town of Dolgoprudny (20 km from the center of Moscow). It is demonstrated that a statistically significant negative correlation between the aerosol particle concentration and the precipitation is observed for monthly mean values only and is absent for semiannual and seasonal means. The analysis of individual cases of precipitation corroborated the conclusion on their low impact on the aerosol concentration in the surface layer. In winter, the aerosol concentration decrease is observed within a narrow particle size interval of 0.03?C0.1 ??m and amounts to not more than 30% during several hours. A scavenging effect of summertime precipitation manifests itself in a wider size interval of 0.03?C1.0 ??m but does not exceed 10?C20% and is of short-term nature. The limited effects of precipitation on the surface aerosol are explained by the proximity to the underlying surface being a permanent aerosol source.     

Estimation of multi-scale temporal variability of air and water temperature in the northeastern part of the Black Sea

Standard deviations of mesoscale, synoptic, seasonal, and interannual fluctuations of the air and water temperature are calculated from long-term measurements. The contributions of each type of fluctuation to the total temporal variability are estimated. The intraannual cycle of variability of monthly (long-term) means of mesoscale and synoptic fluctuations is considered.     

广西45年来降水和气温的长期变化特征

应用1957～2001年广西76站逐月降水量和平均气温资料,通过计算各站降水和气温的趋势系数,分析广西45a来年、季、月降水和气温长期变化的特征。结果表明,广西的年降水量没有明显的长期变化异常,但季、月的降水量表现出不同的长期变化特征;广西的年平均气温有很明显的增温趋势,变暖主要是发生在夏、秋季,而春季气温则有比较明显的下降趋势。     

1951—2010年大连市气温变化特征

利用1951—2010年大连市气温资料,采用气候趋势系数和气候倾向率、Mann-Kendal1突变分析等方法对年和季平均气温、最高最低气温变化特征进行了分析和突变检验。结果表明：大连市年和季平均气温呈上升趋势,进入21世纪,升温趋势有所减缓;大连市年平均气温的增温速率为0.33/10 a,明显高于近50 a中国平均增温速率0.22/10 a,更高于近50 a全球平均0.13/10 a的增温速率。大连市平均气温的升高主要发生在春季和冬季;年平均最低气温的升温幅度大于年平均最高气温的升温幅度;年、季平均气温存在突变,突变始于1987—1990年前后,突变前后平均气温均值相差较大;年、季平均最高气温和最低气温大都存在突变,但秋季平均最高气温无突变。     

1951—2010年大连市气温变化特征

利用1951—2010年大连市气温资料,采用气候趋势系数和气候倾向率、Mann-Kendal1突变分析等方法对年和季平均气温、最高最低气温变化特征进行了分析和突变检验。结果表明：大连市年和季平均气温呈上升趋势,进入21世纪,升温趋势有所减缓;大连市年平均气温的增温速率为0.33/10 a,明显高于近50 a中国平均增温...     

The seasonal cycle of mixed layer temperatures in a global ocean general circulation model

We examine mixed layer temperatures in a global ocean general circulation model subjected to seasonally varying climatological forcing. Harmonic analysis of monthly mixed layer temperatures and climatological sea surface temperatures (SSTs) shows that, on the average, the annual harmonic accounts for 90% of the total seasonal variance in both fields, while the semiannual harmonic accounts for about 8%. The semiannual signal is mostly confined to equatorial and high-latitude regions. The model mixed layer temperatures underestimate the mean amplitude of the annual harmonic in middle latitudes (65°||10°) by about 26%, while lagging climatological SSTs by 22 days, on average. In several parameter sensitivity experiments, these differences could be reduced to as little as 12% and 12.5 days, respectively, though most of this gain occurred when the mixed layer was unrealistically shallow (mean depth less than 65 m). At least part of the differences in amplitudes and phases of the annual harmonic is linked to the uncoupled formulation of the surface heat flux, which is computed using specified and seasonally varying climatological air temperatures. In ice-free areas, seasonal amplitudes and phases of air temperatures are almost identical to those of climatological SSTs. Thus, differences between model mixed layer temperatures and climatological SSTs give rise to Newtonian relaxation to SSTs, which then leads to amplitude damping and time lags in mixed layer temperatures relative to the SSTs.     

Analysis of long time series of long-wave radiation fluxes above a pine forest

Summary ?The long-term variations of upward terrestrial (E) and downward atmospheric (A) long-wave radiation fluxes above a pine stand in the southern part of the upper Rhine valley plain are analysed based on monthly mean values from 27 years of monitoring. Equivalent blackbody temperatures of the canopy and the atmosphere are calculated and compared to air temperatures at nearby sites. Based on 324 monthly values each, correlations between A and E as well as A and global radiation G are analysed. Only the former are highly correlated. Monthly mean values of long-wave radiation A can be calculated from air temperature, water vapour pressure and cloud cover. The long-term yearly average of equivalent blackbody temperature of the canopy is 0.6 K lower than kinetic air temperature at nearby sites. Only small, insignificant increases of both blackbody temperatures and air temperature are found. Despite the strong forest growth, it is surprising that the ratio of canopy emission temperature to air temperature did not change significantly. Relationships between the changes of general atmospheric circulation and equivalent blackbody temperatures of the canopy point to a strong dependence on shifts of general atmospheric flow. Received February 24, 2000; revised April 18, 2002; accepted July 20, 2002     

河源地区气温变化特征及其与ENSO的关系

利用河源地区5个气象站1960—2016年的逐月平均气温、NOAA逐月海温等资料,采用线性倾向、Mann-Kendall检验等统计方法,分析了河源地区气温变化特征及其对ENSO事件的响应。结果表明:河源地区年平均气温及季平均气温均呈递增趋势,且夏、秋、冬季和年平均气温气温上升趋势显著;河源地区气温在20世纪80年代中后期—90年代末发生1次较为明显的由冷到暖的突变;年平均气温存在5~6、14~15及24 a的周期变化规律;在El Ni1o事件中,河源地区年平均气温有偏高趋势,La Ni1o事件,则反之;ENSO事件对气温的影响存在滞后性,对河源地区的气温影响最明显表现在次年。     

南宁市城区空气质量特征的差异

总结分析2002~2006年南宁市各城区逐日、月平均、季平均、年平均空气质量特征的差异。在设有空气质量监测点的青秀区、兴宁区、江南区、西乡塘区4个城区中,空气质量优良率最高的是西乡塘区,占天数的98.1%,其次是为青秀区,最低的是江南区,西乡塘区、青秀区空气质量优于其它城区。各城区的首要空气污染物以可吸入颗粒物为主。各城区逐日、月平均、季平均、年平均空气质量特征均有一定的差异。     

1951—2009年中国不同区域气温和降水量变化特征

为了研究中国不同区域气候变化特征,将全国按照气候区域划分为11个气候区,并利用1951—2009年中国194个国家基本/基准站月、年气温和降水观测资料,对全国及每个气候区平均温度及降水量的年和季节变化特征进行分析。结果表明：中国及各地区增温趋势均为极显著增加,尤其近20 a增温速度更快;而2007年成为有记录以来最暖的...     

濮阳市0 cm地温变化特征及成因分析

利用线性分析方法和相关分析方法,分析了濮阳近50年地面温度的变化倾向率及成因。月平均地面温度变化趋势具有明显的阶段性,12月至翌年4月呈升温趋势,5～11月呈降温趋势,其变化倾向率分别为0．01～0．32℃／10a和-0．04～-0．83℃／10a,年平均地面温度变化倾向率为-0．23℃／10a;各月地面平均最高温度的变化倾向率,11月为0．01℃／10a,其余月份则为-0．46～-2．16℃／10a,年变化倾向率为～0．23℃／10a;各月地面平均最低温度的变化倾向率,11月为-0．02℃／10a,其余月份则为0．09～0．76℃／10a,年变化倾向率为0．34℃／10a;各月平均地气温差的变化倾向率为-0．17～-0．66℃／10a,年变化倾向率为-0．35℃／10a。当地地面平均最高温度呈逐年递减趋势,地面平均最低温度呈逐年递增趋势,地面平均最高温度的递减趋势远大于平均最低温度的递增趋势,因此,年平均地面温度呈逐年递减趋势。地气温差逐年递减,大气稳定度增强,不利于近地层污染物和水汽扩散,由此带来轻雾日数增多,空气污染加重。日照时数减少,地面受太阳直接辐射减少,是地面温度趋降的直接原因,空气湿度和降水量趋增、空气污染加重等要素的变化,是地面温度趋降的间接原因。     

Temperature stratification of the lower atmosphere over Moscow

Features of diurnal and annual cycles and of seasonal changes of temperature stratification in the lower 800-m air layer over Moscow are discussed on the basis of analysis of long-term data of acoustic (sodar) observations at Moscow State University (MSU). Of about 34 000 separate hours of height-time sweep of echo signal during 1988–2003, refined estimates are presented of occurrence frequencies of surface and elevated inversions, unstable stratification, etc., in Moscow. On the basis of long series of hourly sodar data and surface weather observations at MSU, special features of temperature stratification are considered under extremely low and high values of air temperature, wind speed, and relative humidity. A review is presented of existing data on temperature stratification in central Russia for the whole period of aerological observations; results of acoustic sounding are compared against the data obtained using other techniques.     

Seasonal variability of near-surface isothermal layer and thermocline characteristics of the Tropical Indian Ocean

Summary A subset of world ocean monthly mean temperature climatology generated by Levitus and Boyer (1994), is utilised to describe the observed seasonal variability of the characteristics of the near-surface isothermal layer and thermocline for the entire tropical Indian Ocean (TIO). The most salient features of the observed annual cycle are described in terms of amplitude and phase of the annual and semi-annual frequencies employing Fourier analysis technique. On the annual mode, the near-surface isothermal layer depth (ILD), exhibits larger variability away from the equator with peak values in the northernmost Arabian Sea, the northernmost Bay of Bengal and the southern TIO, while on the semi-annual mode, it shows larger variability in the central Arabian Sea. The variability of the near-surface isothermal layer temperature (ILT), on the annual mode, is very weak in the warmpool region, and increases with latitude, while on the semi-annual mode, it shows larger variability in the northwestern Arabian Sea. The variability of 20°C isotherm topography (D20), on the annual mode, is weakest in the equatorial region and largest in the coastal regions of the Arabian Sea and the Bay of Bengal and in the southern T10, while on the semi-annual mode, it is prominent in the eastern and western equatorial regions. The thermocline gradient (TG) is very sharp below the warmpool region and diffuses meridionally. On the annual mode, it shows larger variability in the southern TIO, off Somalia and northernmost Arabian Sea, while on the semiannual mode, it shows larger variability in the southwestern Arabian Sea and eastern equatorial Indian Ocean. The relationship between near-surface isothermal layer and thermocline characteristics over an annual cycle are explored through correlation analysis. The correlation between ILD and ILT is strong over much of the basin with the exception of the equatorial and coastal upwelling/downwelling zones where internal ocean dynamics are important. In the southern TIO, entrainment of colder waters appears to be important in maintaining the annual cycle of ILT as strong correlation is noticed between ILT and TG. In the Indo-Pacific throughflow region and another region west of it, the annual Rossby waves appear to control D20, as correlations between D20 and other fields are strong in these regions. A similar strong correlation between D20 and ILD is also noticed in the southeastern Arabian Sea where mode-2 Rossby waves identified in numerical model solutions.With 5 Figures     

中岳嵩山高山站平均气温资料插补及其变化趋势分析

为明确近60 a来在近对流层自由大气底部这一特定高度上河南省中岳嵩山气温变化特征,在对河南省登封气象站月平均气温数据均一化的基础上,采用该站均一化数据构建嵩山站月平均气温模拟模型,对1990—2002年缺测数据插补,建立中岳嵩山高山国家基准气候站1956—2017年时间序列连续的月平均气温资料,采用线性回归对其进行气温变化趋势分析。结果表明：均一化处理对登封站月平均气温因台站迁移的非自然因素引起的非均一性取得了明显的校正效果。均一化后,1969—2017年登封站年平均气温由显著上升速率0.218℃/10 a增至0.310℃/10 a。利用独立数据对模型进行验证表明,总体上,嵩山站各月平均气温推算模型模拟值与实测值的线性相关系数和斜率分别为0.999和0.989(n=204,P < 0.01);1—12月各月模型验证检验参数的平均值相关系数为0.958、均方根误差为11.7%、平均绝对偏差为0.3℃、平均偏差为0.1℃、拟合指数为0.973、模拟效率为0.900,模型具有较好的模拟效果。1956—2017年嵩山站年平均气温增温显著,其速率为0.223℃/10 a。四季之间,以春季增温速率最大,为0.350℃/10 a;冬季和秋季次之;夏季增温不显著。各月之间,以2月增温速率最大,达0.445℃/10 a。