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Understanding the characteristics of minute‐scale short‐duration intense rainfall and its possible link with urbanization is valuable for addressing urban climate change and evaluating biases in high‐resolution historical precipitation data series. This study analyses the long‐term trends of rainy‐season minute‐scale intense rainfall events at different continuous time periods based on precipitation data from 20 national meteorological stations in the Beijing area covering the period from 1961 to 2021. This study shows that during the whole period analysed, the number of events of intense rainfall lasting 15 min or longer decreased, while the number of shorter‐duration events and the accumulated precipitation increased. The frequency and amount of minute‐scale intense rainfall recorded by urban stations are generally higher than those recorded by rural stations in terms of climatological means. The signal of the urbanization effect in minute‐scale precipitation changes is detectable, with the contribution of urbanization to the trends in average precipitation of 30‐min intense rainfall being 68.8%, whereas the contributions with respect to the frequency of 20‐ and 30‐min intense rainfall and the maximum precipitation of intense rainfall with a duration of 45 min reach 100%. The results of the analysis can provide reference for understanding long‐term changes in short‐duration rainfall and the possibility that they are driven by local anthropogenic activity, as well as bias in the minute‐scale precipitation data series of urban observation sites when they are used in studies of large‐scale intense precipitation changes. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of the effect of urbanization on the surface air temperature (SAT) from 1951 to 2018 in the Philippines. The daily minimum temperature (Tmin) and daily maximum temperature (Tmax) records from 34 meteorological stations were used to derive extreme temperature indices. These stations were then classified as urban or rural based on satellite night‐lights. The results showed a significant difference in the SAT trends between urban and rural stations, indicative of the effect of urbanization in the country. Larger and more significant warming trends were observed in indices related to Tmin than those related to Tmax. In particular, the effects of urbanization were significant in the annual index series of Tmin, diurnal temperature range, minimum Tmin, percentage of days when Tmin was less than the 10th percentile (TN10p), percentage of days when Tmin was greater than 90th percentile (TN90p), and the number of coldest nights. The effects of urbanization were not as clear on the index series of maximum Tmax (TXx), minimum Tmax (TXn), percentage of days when Tmax was less than 10th percentile (TX10p), and the number of hottest days. The effects of urbanization on the annual series of extreme temperature indices were statistically significant at the 95% confidence level, with the exception of Tmax, TXn, TXx, TX10p, and the number of hottest days. Further analysis revealed that the effect of urbanization was the greatest during the DJF (December–January–February) season. These findings serve as a baseline study that focuses on the countrywide effect of urbanization on SAT trends in the Philippines. [ABSTRACT FROM AUTHOR]

Based on a homogenized data set of monthly mean temperature, minimum temperature, and maximum temperature at Shijiazhuang City Meteorological Station (Shijiazhuang station) and four rural meteorological stations selected applying a more sophisticated methodology, we reanalyzed the urbanization effects on annual, seasonal, and monthly mean surface air temperature (SAT) trends for updated time period 1960–2012 at the typical urban station in North China. The results showed that (1) urbanization effects on the long-term trends of annual mean SAT, minimum SAT, and diurnal temperature range (DTR) in the last 53 years reached 0.25, 0.47, and − 0.50 °C/decade, respectively, all statistically significant at the 0.001 confidence level, with the contributions from urbanization effects to the overall long-term trends reaching 67.8, 78.6, and 100%, respectively; (2) the urbanization effects on the trends of seasonal mean SAT, minimum SAT, and DTR were also large and statistically highly significant. Except for November and December, the urbanization effects on monthly mean SAT, minimum SAT, and DTR were also all statistically significant at the 0.05 confidence level; and (3) the annual, seasonal, and monthly mean maximum SAT series at the urban station registered a generally weaker and non-significant urbanization effect. The updated analysis evidenced that our previous work for this same urban station had underestimated the urbanization effect and its contribution to the overall changes in the SAT series. Many similar urban stations were being included in the current national and regional SAT data sets, and the results of this paper further indicated the importance and urgency for paying more attention to the urbanization bias in the monitoring and detection of global and regional SAT change based on the data sets. [ABSTRACT FROM AUTHOR]

Based on daily temperature data from an urban station and four rural stations of Shijiazhuang area in Hebei Province, North China, we analyzed the trends of extreme temperature indices series of the urban station (Shijiazhuang station) and rural stations during 1962-2011 and the urbanization effect on the extreme temperature indices of the urban station. The results showed that the trends of annual extreme temperature indices of the urban station and the rural stations are significantly different in the recent 50 years. Urbanization effect on the long-term trends of hot days, cold days, frost days, diurnal temperature range (DTR), extreme maximum temperature, and extreme minimum temperature at the urban station were all statistically significant, reaching 1.10 days/10 years, −2.30 days/10 years, −2.55 days/10 years, −0.20 °C/10 years, 0.16 °C/10 years, and 0.70 °C/10 years, respectively, with the urbanization contributions to the overall trends reaching 100, 38.0, 42.2, 40.0, 94.1, and 47.0 %, respectively. The urbanization effect on trend of ice days was also significant, reaching −0.47 days/10 years. However, no significant urbanization effect on trends of minimum values of maximum temperature and maximum values of minimum temperature had been detected. The urbanization effects in the DTR and extreme minimum temperature series of Shijiazhuang station in wintertime were highly significant. [ABSTRACT FROM AUTHOR]

The aim of the study is to estimate the trend in extreme temperature events in the northern part of Korean Peninsula during 1960–2019, as well as to conduct a comparison experiment with the other representative results, all trends are examined based on quality-controlled daily maximum and minimum temperature data from 37 weather stations. Results are as follows. First, frost days (FD0) and ice days (ID0) showed a clear downward trend, whereas warm days (SU25) and warm nights (TR20) experienced an obvious uptrend, with SU25 exceeding TR20, while very hot days (TX35), extreme hot days (TX37) and very extreme hot days (TX39) showed abrupt increasing trends, especially twice in TX37 and six times in TX39, respectively. Both of cold nights (TN10) and cold days (TX10) decreased by about −0.7d/decade, hot nights (TN90) and hot days (TX90) increased by 0.6d and 1.0d/decade, respectively. Second, as compared with to representative results in global by the relevant reference and study period, all uptrends in TR20, SU25 and annual maximum of daily maximum temperature (TXx) were significantly higher than those in most regions in China, SU25 and TR20 were mostly greater than those in most regions, except for some regions in Europe. In particular, TR20 upward trend exceeded any other region's results. Meanwhile, TX10 and TNn experienced stronger downward and upward tendencies than those in whole China respectively. Especially, TNn experienced the strongest upward trend in comparing with the others. Overall, results revealed hot weather frequency and nighttime warm events over the study area have experienced a larger increasing trend than those in global land. • Cold-Cool extreme events represented downtrends, the crosscurrents in Hot-Warm ones. • Extreme hot weather events during summer had experienced a strong uptrend. • Uptrends in some extreme events were the largest in comparative regions in global. [ABSTRACT FROM AUTHOR]

An hourly dataset of automatic weather stations over Beijing Municipality in China is developed and is employed to analyze the spatial and temporal characteristics of urban heat island intensity (UHII) over the built-up areas. A total of 56 stations that are located in the built-up areas [inside the 6th Ring Road (RR)] are considered to be urban sites, and 8 stations in the suburban belts surrounding the built-up areas are taken as reference sites. The reference stations are selected by using a remote sensing method. The urban sites are further divided into three areas on the basis of the city RRs. It is found that the largest UHII generally takes place inside the 4th RR and that the smallest ones occur in the outer belts of the built-up areas, between the 5th RR and the 6th RR, with the areas near the northern and southern 6th RR experiencing the weakest UHI phenomena. On a seasonal basis, the strongest UHII generally occurs in winter and weak UHII is dominantly observed in summer and spring. The UHII diurnal variations for each of the urban areas are characterized by a steadily strong UHII stage from 2100 local solar time (LST) to 0600 LST and a steadily weak UHII stage from 1100 to 1600 LST, with the periods 0600-1100 LST and 1600-2100 LST experiencing a swift decline and rise, respectively. UHII diurnal variation is seen throughout the year, but the steadily strong UHII stage at night is longer (shorter) and the steadily weak UHII stage during the day is shorter (longer) during winter and autumn (summer and spring). [ABSTRACT FROM AUTHOR]

Cold and warm temperature extremes predominantly occurring in winter gained much more attention than mean temperatures. On the basis of daily maximum and minimum surface air temperature records at 303 meteorological stations in China, the spatial and temporal distributions of five indices for winter (DJF: December, subsequent January and February) temperature extremes are analysed during 1961-2003. For the majority of stations, the frequency of cold days/nights decreases by − 1.33/− 2.98 and warm days/nights increases by 0.92/2.35 d/decade, respectively. Cold days/nights are significantly negatively correlated with the Arctic Oscillation (AO) index, while warm days/nights are positively correlated with the AO. The diurnal temperature range (DTR) has a declining trend with rate of − 0.25 °C/decade and positive correlation with the AO index. Compared with other regions in China, stations in the northern China have larger trend magnitudes and stronger correlations with the AO index, and the AO can explain more than 50% of winter temperature extreme change in China. Compared with the annual basis, the winter temperature extremes have larger trend magnitudes, which reflect the rapid warming. During strongly positive AO index years, enhanced contrast tropospheric temperature (defined as the average of air temperature vertically integrated between 200 hPa and 1000 hPa based on the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis) between the north of China and the southern China weakens the East Asian winter monsoon which in turn reduces cold outbreaks in the northern and eastern China. The composites of large-scale atmospheric circulation are consistent with the asymmetrical changes of the geopotential height, zonal and meridional winds at high and mid latitudes at troposphere. Meanwhile, the linkage between the AO and solar activity also modulates the winter temperature extremes, while the mechanism needs to be investigated. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

In the global lands, the bias of urbanization effects still exits in the surface air temperature series of many city weather stations to a certain extent. Reliable reference climate stations need to be selected for the detection and correction of the local manmade warming bias. The underlying image data of remote sensing retrieval is adopted in this study to obtain the spatial distribution of surface brightness temperature, and the surface air temperature reference stations are determined based on the locations of the weather stations in the remote sensing surface thermal fields. Among the 672 national reference climate stations and national basic weather stations of mainland China, for instance, 113 surface air temperature reference stations are selected for applying this method. Compared with the average surface air temperature series of the reference stations obtained by a more sophisticated method developed in China, this method is proven to be robust and applicable, and can be adopted for the evaluation and adjustment study on the urbanization bias of the currently used air temperature records of surface climate stations in the global lands. [ABSTRACT FROM AUTHOR]

The article presents an analysis of spatial and temporal changes of temperature and precipitation at 143 weather stations in ten Asia-Pacific Network (APN) countries from 1955 until 2007. The study highlights annual and seasonal changes in temperature means and extreme events. Meanwhile, this researchdemonstrate shortcomings of indices based on set thresholds which investigate extreme climate events across the regions acquiring multiple climate zones.

The frequent occurrence of extremely high temperatures and heatwaves (HWs), combined with the urban heat island (UHI) effect, significantly affects building energy consumption. This study is performed to investigate the impacts of UHI on building cooling demand during HW periods in megacities. Thus, we examine a typical HW event in late June and early July of 2018, which is classified into HW and non-HW periods, in the two megacities of Beijing and Tianjin. Based on hourly meteorological observation data and rural weather stations selected using satellite-based methodology, the impacts of the UHI on the hourly cooling loads of typical residential and office buildings are evaluated by simulating the hourly cooling loads during the HW event. The results show that the hourly maximum urban heat island intensity (UHII) in Beijing and Tianjin reached 8.4 °C and 5.7 °C during the HW period, respectively. The cooling load of the buildings as well as the urban-rural load difference increased significantly when HWs occurred. The urban-rural hourly load difference of the office buildings is greater than that of the residential buildings. During nighttime, the urban-rural hourly load difference of the residential buildings increased, and the peak value occurred between 02:00 LST and 04:00 LST, which is more evident in Beijing than in Tianjin. For every 1 °C increase in the UHII, the hourly cooling load of the residential buildings (office buildings) in the urban areas increased by 0.5 × 10−3 kWh/m2 (1.4 × 10−3 kWh/m2) compared with that in the rural areas. These findings should be considered in the building design and operation regulation of energy saving, particularly the impacts of extreme HWs and UHI on peak loads, to reduce energy consumption and carbon emissions in other megacities located at similar latitudes and with similar conditions as those of Beijing and Tianjin. • Considered the impacts of UHI on building cooling demand during heatwave. • Urban daily loads of the residential buildings (Office buildings) increased by 10–40% (10%). • Peak cooling demand: 13:00 LST (Residential buildings); 13:00–14:00 LST (Office buildings). • During nighttime, the urban-rural cooling load differences of residential buildings increased. • Urban-rural cooling load differences increased when UHII exceeded approximately 2 °C. [ABSTRACT FROM AUTHOR]