Regional Temperature Changes Research Articles

Amplification Effect of Urbanization on Atmospheric Aridity Over China Under Past Global Warming

AbstractWhile it is well known that rapid urbanization poses prominent effects on regional or local temperature changes under global warming, possible impacts of urbanization on the changes in atmospheric aridity (measured by vapor pressure deficit [VPD]) are poorly understood. In this study, we provide a national investigation of the spatiotemporal changes of atmospheric aridity over China in recent decades by analyzing observations at over 2,000 weather stations across China during 1971–2017 and further quantify the effects of urbanization on the atmospheric aridity changes in different subregions. The results show that most parts of China have experienced a significant intensification of atmospheric aridity since the 1970s. Especially, stronger drying trends tend to appear in urban agglomerations with higher urbanization levels and denser population, such as Beijing‐Tianjin‐Hebei (BTH), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), and the Sichuan Basin. It is estimated that urbanization contributed to more than 30% of the total increases in atmospheric aridity in urban core areas (i.e., 32.58%, 27.73%, 30.29%, 42.03%, and 37.33%, respectively, for annual, spring, summer, autumn, and winter VPD). Spatially, urbanization exerted significant amplification effects on increasing VPD in most parts of China (nearly 80% grid cells) except for few areas with higher elevation and complex topography (e.g., Qinghai‐Tibet Plateau and Xinjiang). In particular, the areas with higher urbanization (e.g., BTH, YRD, and PRD) underwent even stronger urbanization effects on amplifying atmospheric aridity. Our findings suggest that how to alleviate atmospheric aridity in future urban planning is worthy of consideration.

Regional Construction and Differences of Thermal Environment in Vernacular Buildings

Unlike the traditional extensive heating management, the on-demand precise time- and region-specific heating strategy can effectively reduce the heating energy consumption of vernacular buildings. The existing studies on the time- and region-specific heating strategy of vernacular buildings face several problems: the time and space are not clearly divided, the heating model cannot simultaneously satisfy the different heating demands of residents in different periods, and the proper time- and region-specific heating terminals are severely lacking. To solve these problems, this paper explores the regional construction and differences of thermal environment in vernacular buildings. Firstly, we classified the regional construction of thermal environment in vernacular buildings, analyzed the thermal process for the regional construction, and determined the implementation model for heating actual vernacular buildings. The layout of rooms inside a multi-space vernacular building determines the difference in heat gain and loss between the rooms to be heated, when the heating system operates naturally. With this in mind, we analyzed the regional thermal balance of thermal environment in vernacular buildings, linearly fitted the average indoor thermal sensation in each region of a vernacular building in day and night, and obtained the relevant experimental results. In addition, the regional indoor temperature changes were summarized at different glazing ratios and different roof heat transfer resistances. The results show the effectiveness of the regional construction strategy of thermal environment based on time and regional differences.

Initial oak regeneration responses to experimental warming along microclimatic and macroclimatic gradients.

Quercus spp. are one of the most important tree genera in temperate deciduous forests in terms of biodiversity, economic and cultural perspectives. However, natural regeneration of oaks, depending on specific environmental conditions, is still not sufficiently understood. Oak regeneration dynamics are impacted by climate change, but these climate impacts will depend on local forest management and light and temperature conditions. Here, we studied germination, survival and seedling performance (i.e. aboveground biomass, height, root collar diameter and specific leaf area) of four oak species (Q. cerris, Q. ilex, Q. robur and Q. petraea). Acorns were sown across a wide latitudinal gradient, from Italy to Sweden, and across several microclimatic gradients located within and beyond the species' natural ranges. Microclimatic gradients were applied in terms of forest structure, distance to the forest edge and experimental warming. We found strong interactions between species and latitude, as well as between microclimate and latitude or species. The species thus reacted differently to local and regional changes in light and temperature ; in southern regions the temperate Q. robur and Q. petraea performed best in plots with a complex structure, whereas the Mediterranean Q. ilex and Q. cerris performed better in simply structured forests with a reduced microclimatic buffering capacity. The experimental warming treatment only enhanced height and aboveground biomass of Mediterranean species. Our results show that local microclimatic gradients play a key role in the initial stages of oak regeneration; however, one needs to consider the species-specific responses to forest structure and the macroclimatic context.

The Future Extreme Temperature under RCP8.5 Reduces the Yields of Major Crops in Northern Peninsular of Southeast Asia.

This study explores the impact of rising near-future temperatures on crop yields, particularly rice and maize, in northern Thailand between 2020 and 2029. The potential for high temperatures in northern Thailand between 2020 and 2029 under the Representative Concentration Pathways 8.5 (RCP8.5) scenario indicates that Thailand experienced hot trends between 2020 and 2029 as measured by the annual maximum value of daily maximum temp (TXx), annual minimum value of daily maximum temp (TXn), annual minimum value of daily minimum temp (TNn), and annual maximum value of daily minimum temp (TNx). Northern Thailand had the most dramatic changes in TXn and TNn. Furthermore, TXn levels were found to be significantly higher in northern Thailand. The number of days when TX < 10th percentile (TX10p) intensity decreased, while the number of days with TN < 10th percentile (TN10p) intensity was increasing. The number of days when TN > 90th percentile (TX90p) has become increasingly rare in northern Thailand. The TN90p was dropping in northern Thailand, whereas the Warm Spell Duration Index (WSDI) was growing. Additionally, the cold spell duration index (CSDI) continues to decline. This indicates that the heat persistence index is increasing in northern Thailand. Temperature rises are the most likely to have a detrimental impact on agricultural production, and climate models can predict regional temperature changes with more precision than precipitation. Throughout the planting season (June-December), average yearly temperatures in rice and maize growing areas have climbed by 0.5–0.6°C. The impact estimates for maize and rice are generally negative, that is, −10 ± 4.6% per °C and −8 ± 3.5% per °C, respectively.

Water-pumping and purifying hydrogels driven by diurnal temperature variation

Diurnal temperature variation is an untapped energy source, although it has seldom been exploited as such. In this study, a novel system of thermo-responsive hydrogels uses diurnal temperature variation as the only power source to pump and purify water. Water is pumped at night and released during the day using an anisotropic xylem-mimetic structure whose composite phase functions as a water channel valve. The water-pumping efficiency ranges from 78% to 92%, and the weights of the pumped water per cycle are 2–3 times larger than those of the pumping materials. The anisotropic structure and the hydrophobic silicone phase are critical in determining pumping efficiency, which allow irreversible water flow upon temperature variation. Seasonal and regional temperature changes can be matched using thermo-responsive hydrogels with different volume transition temperatures. Purification of dye-contaminated water and separation of oil–water mixtures are also successfully achieved based on the hydrophilic and the pollutant-adsorbing nature of hydrogels. Since temperature changes even faster than the diurnal temperature cycle can also power this water pumping and purification system, this novel mechanism could provide a new operational solution for future water management.

Calculating the Climatology and Anomalies of Surface Cloud Radiative Effect Using Cloud Property Histograms and Cloud Radiative Kernels

Cloud radiative kernels (CRK) built with radiative transfer models have been widely used to analyze the cloud radiative effect on top of atmosphere (TOA) fluxes, and it is expected that the CRKs would also be useful in the analyses of surface radiative fluxes, which determines the regional surface temperature change and variability. In this study, CRKs at the surface and TOA were built using the Rapid Radiative Transfer Model (RRTM). Longwave cloud radiative effect (CRE) at the surface is primarily driven by cloud base properties, while TOA CRE is primarily decided by cloud top properties. For this reason, the standard version of surface CRK is a function of latitude, longitude, month, cloud optical thickness (τ) and cloud base pressure (CBP), and the TOA CRK is a function of latitude, longitude, month, τ and cloud top pressure (CTP). Considering that the cloud property histograms provided by climate models are functions of CTP instead of CBP at present, the surface CRKs on CBP-τ histograms were converted to CTP-τ fields using the statistical relationship between CTP, CBP and τ obtained from collocated CloudSat and MODIS observations. For both climate model outputs and satellites observations, the climatology of surface CRE and cloud-induced surface radiative anomalies calculated with the surface CRKs and cloud property histograms are well correlated with those calculated from surface radiative fluxes. The cloud-induced surface radiative anomalies reproduced by surface CRKs and MODIS cloud property histograms are not affected by spurious trends that appear in Clouds and the Earth’s Radiant Energy System (CERES) surface irradiances products.

Method for monitoring regional environmental temperature change data based on 5G internet of things technology

Method for monitoring regional environmental temperature change data based on 5G internet of things technology

On the dependency of GCM-based regional surface climate change projections on model biases, resolution and climate sensitivity

We investigate the dependency of projected regional changes in surface air temperature (SAT) and precipitation on the model biases, resolution and global temperature sensitivity in two global climate model (GCM) ensembles. End of twenty-first century changes under high end scenarios normalized in units of per degree of global warming (PDGW) are examined for CMIP5 (RCP8.5) and CMIP6 (SSP5-8.5) ensembles of comparable size over 26 sub-continental scale regions, for December–January–February (DJF) and June–July–August (JJA). A brief analysis is also carried out for the scenario SSP3-7.0, which shows results essentially in line with the SSP5-8.5 ones. We find that the average regional change patterns are very similar between the CMIP5 and CMIP6 ensembles, both for SAT and precipitation, with spatial correlations exceeding 0.84. Also similar are the regional bias patterns over most regions analyzed, suggesting that these two generations of models still share some common systematic errors. A statistically significant relationship between projected regional changes and biases is found in 27% of regional cases for both SAT and precipitation; between regional changes and model resolution in 2% of cases for SAT and 12% of cases for precipitation; and between regional changes and global temperature sensitivity in 19% of cases for SAT and 14% of cases for precipitation. Therefore, we assess that the GCM resolution does not appear to be a significant factor in affecting the sub-continental scale projected changes, at least for the resolution range in the CMIP5 and CMIP6 models, while global temperature sensitivity and especially model biases play a more important role. These dependencies are not always consistent between the CMIP5 and CMIP6 ensembles. Overall, in our assessment the CMIP6 ensemble does not appear to provide substantially different, and presumably improved, regional surface climate change information compared to CMIP5 despite the use of more comprehensive models and somewhat higher resolution.

Changes in the Snow Cover Extent in Eurasia from Satellite Data in Relation to Hemispheric and Regional Temperature Changes

Changes in the Snow Cover Extent in Eurasia from Satellite Data in Relation to Hemispheric and Regional Temperature Changes

Climate on the Blanca Massif, Sangre de Cristo Mountains, Colorado, USA, during the Last Glacial Maximum

Temperature-index modeling is used to determine the magnitude of temperature depression on the Blanca Massif, Colorado, required to maintain steady-state mass balances of nine reconstructed glaciers at their extent during the Last Glacial Maximum (LGM). The mean temperature depression thus determined is ~8.6 +0.7/−0.9 °C where the uncertainties account for those inherent in the glacier reconstructions, in model parameters (e.g., melt factors), and possible modest changes in LGM precipitation. Associated equilibrium-line altitudes (ELAs) exhibit a statistically significant directional dependency being lower toward the north and east. Under the assumption that regional temperature change was uniform, required changes in precipitation vary systematically—also exhibiting a directional dependency coinciding with that in ELAs—and indicate increases (over modern) occurred on the eastern side of the massif while decreases occurred on the western side. This disparity represents a strengthening of a precipitation asymmetry, particularly winter precipitation, which exists today. The modern precipitation asymmetry may be a consequence of snow being blown over to the eastern side of the massif (advective transport) by southwesterly flow. Intensification of this flow during the LGM would have enhanced advection, and augmented snow accumulation on glaciers, thus explaining the lower ELAs and increased precipitation on that side of the massif.

Modifying emissions scenario projections to account for the effects of COVID-19: protocol for CovidMIP

Abstract. Lockdowns to avoid the spread of COVID-19 have created an unprecedented reduction in human emissions. While the country-level scale of emissions changes can be estimated in near real time, the more detailed, gridded emissions estimates that are required to run general circulation models (GCMs) of the climate will take longer to collect. In this paper we use recorded and projected country-and-sector activity levels to modify gridded predictions from the MESSAGE-GLOBIOM SSP2-4.5 scenario. We provide updated projections for concentrations of greenhouse gases, emissions fields for aerosols, and precursors and the ozone and optical properties that result from this. The code base to perform similar modifications to other scenarios is also provided. We outline the means by which these results may be used in a model intercomparison project (CovidMIP) to investigate the impact of national lockdown measures on climate, including regional temperature, precipitation, and circulation changes. This includes three strands: an assessment of short-term effects (5-year period) and of longer-term effects (30 years) and an investigation into the separate effects of changes in emissions of greenhouse gases and aerosols. This last strand supports the possible attribution of observed changes in the climate system; hence these simulations will also form part of the Detection and Attribution Model Intercomparison Project (DAMIP).

Combining sparse observations and reanalysis data for refining spatiotemporal variability in near‐surface air temperature lapse rates over China

AbstractUneven and sparse surface air temperature (Ta) observations challenge the understanding of the atmosphere‐land interactions and global environmental changes. Lapse rate () is thought of with great potential to obtain accurate long‐term and high‐resolution Ta dataset. However, previous studies on over China were solely based on observed data, which limited our understanding since few stations are distributed in western China. In this study, an improved procedure for estimating by combining sparse observations and newly released ERA5 reanalysis data was proposed. The spatial heterogeneity in over China and its influencing factors (e.g., topography, climate, and vegetation) were then explored. A re‐examination of long‐term spatiotemporal variations in and its potential driving forces over China was also performed at grid scales. The results demonstrated that our estimations reproduced similar patterns to those derived from observations. The subsequent analyses revealed that the annual and seasonal variability in varied substantially among different altitude gradients, land cover types, and climate zones. The vital role played by vegetation covers in regulating local was emphasized in this study, which was poorly assessed previously. Moreover, in low altitude zones showed lower values but strong temporal fluctuations and contributed more to the interannual variability in over China, which could be mainly attributed to human activities. The present findings can provide an alternative method for estimating and be further used to assess regional or global temperature changes.

Responses of Arctic black carbon and surface temperature to multi-region emission reductions: a Hemispheric Transport of Air Pollution Phase 2 (HTAP2) ensemble modeling study

Abstract. Black carbon (BC) emissions play an important role in regional climate change in the Arctic. It is necessary to pay attention to the impact of long-range transport from regions outside the Arctic as BC emissions from local sources in the Arctic were relatively small. The task force Hemispheric Transport of Air Pollution Phase 2 (HTAP2) set up a series of simulation scenarios to investigate the response of BC in a given region to different source regions. This study investigated the responses of Arctic BC concentrations and surface temperature to 20 % anthropogenic emission reductions from six regions in 2010 within the framework of HTAP2 based on ensemble modeling results. Emission reductions from East Asia (EAS) had the most (monthly contributions: 0.2–1.5 ng m−3) significant impact on the Arctic near-surface BC concentrations, while the monthly contributions from Europe (EUR), Middle East (MDE), North America (NAM), Russia–Belarus–Ukraine (RBU), and South Asia (SAS) were 0.2–1.0, 0.001–0.01, 0.1–0.3, 0.1–0.7, and 0.0–0.2 ng m−3, respectively. The responses of the vertical profiles of the Arctic BC to the six regions were found to be different due to multiple transport pathways. Emission reductions from NAM, RBU, EUR, and EAS mainly influenced the BC concentrations in the low troposphere of the Arctic, while most of the BC in the upper troposphere of the Arctic derived from SAS. The response of the Arctic BC to emission reductions in six source regions became less significant with the increase in the latitude. The benefit of BC emission reductions in terms of slowing down surface warming in the Arctic was evaluated by using absolute regional temperature change potential (ARTP). Compared to the response of global temperature to BC emission reductions, the response of Arctic temperature was substantially more sensitive, highlighting the need for curbing global BC emissions.

Synoptic and meteorological drivers of regional ozone pollution events in China

Surface ozone (O3) pollution events are becoming more frequent and have recently emerged as a severe air pollution problem in China. However, the spatial–temporal distribution of surface O3, as well as its primary synoptic and meteorological drivers, remains poorly understood. The purpose of this study was to identify the key synoptic and meteorological drivers of O3 pollution in different regions of China. To achieve this goal, this study established meteorology overlaps of regional O3 pollution events in space and time and applied a comprehensive statistical model selection method for optimal synoptic and meteorological models, based on a newly released O3 dataset for 2015–2018. It was observed that extreme regional O3 pollution events (duration >7 d) occurred more frequently and exhibited a high co-occurrence frequency (>50%) with air stagnation (AS). Moreover, the beginning and end of 69% of the regional O3 pollution events coincided with regional daily maximum temperature changes. The intensity of AS is the dominant driver of O3 pollution event intensity across most of the six selected megacity regions. Although other meteorological drivers, such as the intensity of hot days (HD) and meridional wind of 10 m were also important, their impacts varied according to the region. Overall, increase in extreme AS and HD led to the worsening of regional O3 pollution events. These findings imply that mitigating regional O3 pollution should consider changing synoptic and meteorological conditions.

A 21st Century Warming Threshold for Sustained Greenland Ice Sheet Mass Loss

AbstractUnder anticipated future warming, the Greenland ice sheet (GrIS) will pass a threshold when meltwater runoff exceeds the accumulation of snow, resulting in a negative surface mass balance (SMB &lt; 0) and sustained mass loss. Here, we dynamically and statistically downscale the outputs of an Earth system model to 1 km resolution to infer that a Greenland near‐surface atmospheric warming of 4.5 ± 0.3°C—relative to preindustrial—is required for GrIS SMB to become persistently negative. Climate models from CMIP5 and CMIP6 translate this regional temperature change to a global warming threshold of 2.7 ± 0.2°C. Under a high‐end warming scenario, this threshold may be reached around 2055, while for a strong mitigation scenario it will likely not be passed. Depending on the emissions scenario taken, our method estimates 6–13 cm sea level rise from GrIS SMB by the year 2100.

Climate change-induced economic impact assessment by parameterizing spatially heterogeneous CO2 distribution

The spatially heterogeneous distribution of CO2 concentrations is an uncertain factor in the assessment of climate change impact. We developed and calibrated a simple climate module to project regional temperature increases using atmospheric simulation output data from the Coupled Model Inter-comparison Project Phase 6 (CMIP6). We compared the differences in regional atmospheric temperature changes arising from spatially homogeneous and heterogeneous distributions of CO2 and assessed economic loss. The results indicated that spatially heterogeneous distribution of CO2 affected the projection of regional temperature increases, with faster temperature rises in industrially advanced regions. Compared with a homogeneous distribution, economic damage was aggravated in the Northern Hemisphere using a heterogeneous distribution, especially in middle-latitude regions. China saw increases in economic damage of 0.030%, 0.007%, and 0.002% in 2100 under SSP5-RCP8.5, SSP2-RCP4.5, and SSP1-RCP2.6, respectively. This suggests that impact assessments that ignore spatially heterogeneous CO2 concentrations could lead to inaccurate estimates of climate damage. These findings indicate that it is necessary to parameterize the spatial distribution of CO2 in traditional climate change assessments. The results provide a more accurate estimation of regional temperature increases and climate change-induced economic damage to support policymaking for mitigation and adaptation.

Heatwaves and Summer Urban Heat Islands: A Daily Cycle Approach to Unveil the Urban Thermal Signal Changes in Lisbon, Portugal

Lisbon is a European Mediterranean city, greatly exposed to heatwaves (HW), according to recent trends and climate change prospects. Considering the Atlantic influence, air temperature observations from Lisbon’s mesoscale network are used to investigate the interactions between background weather and the urban thermal signal (UTS) in summer. Days are classified according to the prevailing regional wind direction, and hourly UTS is compared between HW and non-HW conditions. Northern-wind days predominate, revealing greater maximum air temperatures (up to 40 °C) and greater thermal amplitudes (approximately 10 °C), and account for 37 out of 49 HW days; southern-wind days have milder temperatures, and no HWs occur. Results show that the wind direction groups are significantly different. While southern-wind days have minor UTS variations, northern-wind days have a consistent UTS daily cycle: a diurnal urban cooling island (UCI) (often lower than –1.0 °C), a late afternoon peak urban heat island (UHI) (occasionally surpassing 4.0 °C), and a stable nocturnal UHI (1.5 °C median intensity). UHI/UCI intensities are not significantly different between HW and non-HW conditions, although the synoptic influence is noted. Results indicate that, in Lisbon, the UHI intensity does not increase during HW events, although it is significantly affected by wind. As such, local climate change adaptation strategies must be based on scenarios that account for the synergies between potential changes in regional air temperature and wind.

Wintering bird communities are tracking climate change faster than breeding communities.

Global climate change is driving species' distributions towards the poles and mountain tops during both non-breeding and breeding seasons, leading to changes in the composition of natural communities. However, the degree of season differences in climate-driven community shifts has not been thoroughly investigated at large spatial scales. We compared the rates of change in the community composition during both winter (non-breeding season) and summer (breeding) and their relation to temperature changes. Based on continental-scale data from Europe and North America, we examined changes in bird community composition using the community temperature index (CTI) approach and compared the changes with observed regional temperature changes during 1980-2016. CTI increased faster in winter than in summer. This seasonal discrepancy is probably because individuals are less site-faithful in winter, and can more readily shift their wintering sites in response to weather in comparison to the breeding season. Regional long-term changes in community composition were positively associated with regional temperature changes during both seasons, but the pattern was only significant during summer due to high annual variability in winter communities. Annual changes in community composition were positively associated with the annual temperature changes during both seasons. Our results were broadly consistent across continents, suggesting some climate-driven restructuring in both European and North American avian communities. Because community composition has changed much faster during the winter than during the breeding season, it is important to increase our knowledge about climate-driven impacts during the less-studied non-breeding season.

Recent Shift in the Warming of the Southern Oceans Modulated by Decadal Climate Variability

AbstractIt has been reported that the Southern Hemisphere oceans experienced rapid warming during the decade‐long global surface warming slowdown (2003–2012) and the earlier period of the Argo record (2006–2013). In this study, we analyze updated observations to show that this rapid warming has slowed down, leading to less contribution of the Southern Hemisphere oceans to the global ocean heat storage (∼65% over the available Argo period 2006–2019). Two warming hotspot regions, the southeast Indian Ocean and South Pacific Ocean, have experienced cooling over 2013–2019. This decadal shift is related to variations in the Southern Annular Mode and Interdecadal Pacific Oscillation. The isopycnal deepening (shoaling) forced by changing winds dominated the regional ocean temperature changes over the earlier warming (later cooling) period. Our finding demonstrates how decadal variability modulates long‐term climate change and provides important observational information for the ongoing calibration of decadal prediction systems.

我国三大城市群地区城市和农业用地地表热环境效应对比研究

以大中小城市协同发展为特征的城市群已成为我国城市化发展的主要形式，城市化和农业作为城市群地区最主要的土地利用活动，其气候效应是国际研究的热点。然而过去研究多关注大城市的热岛效应，对更为普遍的农业活动以及中小城市城市化的气候效应认识十分薄弱。基于MODIS地表温度数据，以自然林地为参照，提出了一种可逐像元估算土地利用地表热环境效应的新方法，进而对比分析了我国三大城市群地区（京津冀、长三角和珠三角）城市和农业用地地表热环境效应及其驱动因子差异。结果表明各城市群白天城市热岛效应明显，地级以上城市年平均热岛强度达3.2℃以上，但最强热岛均未发生在核心城市。夜晚热岛效应明显减弱，京津冀和长三角部分城市甚至出现冷岛效应。农业用地在白天亦表现出明显的增温效应，特别是在京津冀地区，而在夜晚除珠三角城市群外，降温效应明显，京津冀和长三角地区平均降温2.3℃和0.7℃。虽然城市用地平均增温强度大于农业用地，但农业用地因面积优势对区域温度变化起控制作用。白天城市和农业用地整体导致各城市群温度明显增加，京津冀增温最高（4.0℃），夜晚二者导致长三角和京津冀地区平均温度降低。研究还发现各城市群城市和农业用地地表热环境效应时空异质性极大，主要受植被、地表反照率、气候背景和人口密度控制。本文对制定缓解气候变化的土地利用策略具有重要的指导意义。;Urban agglomerations, characterized by the synergetic development of large, medium, and small cities, are becoming the main form of urbanization in China. The climate effects of urbanization and agriculture, two most pervasive land use activities, have been the subject of active investigation. However, previous studies focused mainly on the urban heat island (UHI) effect of mega cities, while the climate effects of the more widespread agricultural activities and the urbanization in small/medium cities remain poorly understood. Using natural forests as reference, we proposed a new method to estimate the surface thermal environmental effects of human land use activities on a per-pixel basis based on MODIS land surface temperature (LST). We then compared the thermal effects of urban and agricultural lands and their drivers in three major urban agglomerations, China, namely Beijing-Tianjin-Hebei (BTHUA), Yangtze River Delta (YRDUA), and Pearl River Delta (PRDUA). Results showed that the daytime UHI effects were significant in all the urban agglomerations, with annual mean intensity larger than 3.2 ℃ for all the cities above prefecture-level, but the strongest did not occur in the core cities. The UHI effects reduced substantially at night, and even turned to be cold islands in some cities of the BTHUA and YRDUA. The agricultural lands also warmed the LST substantially during the daytime, especially in the BTHUA. Whereas they cooled the LST obviously at night for the BTHUA and YRDUA, with annual mean intensity of 2.3 ℃ and 0.7 ℃, respectively. Although the urban lands had greater warming potentials, the agricultural lands dominated the regional temperature changes due to their larger area share. The urban and agricultural lands together warmed the daytime LST in all urban agglomerations, with the greatest LST increase in the BTHUA (4.0 ℃), and cooled the LST at night for the BTHUA and YRDUA. Also, this study indicated that the surface thermal environmental effects of urban and agricultural lands varied greatly with the space and time. They were mainly controlled by vegetation activities, surface albedo, background climate, and population density. Our results provide important insights for formulating local land use strategies to mitigate climate change.