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Hourly meteorological data and multisource socioeconomic data collected in the Yangtze River Delta (YRD) region were used to analyze its heat vulnerability during the record-breaking hot summer of 2022 in both daytime and nighttime. Over forty consecutive days, daytime temperatures exceeded 40 °C, and 58.4% of the YRD region experienced 400 h with temperatures hotter than 26 °C during the nighttime. Only 7.5% of the YRD region was under low heat risk during both daytime and nighttime. Strong heat risk combined with strong heat sensitivity and weak heat adaptability led to strong heat vulnerability during both daytime and nighttime in most areas (72.6%). Inhomogeneity in heat sensitivity and heat adaptability further aggravated the heterogeneity of heat vulnerability, leading to compound heat vulnerability in most regions. The ratios of heat-vulnerable areas generated by multiple causes were 67.7% and 79.3% during daytime and nighttime, respectively. For Zhejiang and Shanghai, projects designed to decrease the urban heat island effect and lower the local heat sensitivity are most important. For Jiangsu and Anhui, measures aiming to decrease the urban heat island effect and improve heat adaptability are most important. It is urgent to take efficient measures to address heat vulnerability during both daytime and nighttime.

The increasing rate of the observed daily minimum temperatureTminhas been much higher than that of the observed daily maximum temperatureTmaxduring the past six decades across China. In this study, the local urbanization impact on these observed asymmetric warming rates was investigated. The latest released land-cover data with a 30-m spatial resolution and annual temporal resolution from 1985 to 2017 were used to quantify the urbanization ratios around weather stations. Although urbanized areas occupied only 2.25% of the landmass in China, the percentage of stations with an urbanization ratio over 20% increased from 22.1% to 68.2% during the period 1985–2017. Significant asymmetric warming rates at urban stations were identified, which were approximately 3 times larger compared to the average asymmetry observed at all 2454 stations in China. However, this asymmetry disappeared at rural stations. These differences are mainly due to the rapid local urbanization around most meteorological stations in China since 1985, which affected the spatial representation of observations and led to the observed asymmetry warming rates. The results reported here indicate that the observed asymmetric warming rate over China from 1985 to 2017 is an observational bias due to local urbanization around most stations rather than large-scale climate change. The results also explain the phenomenon that the observed warming rate ofTminremains higher than that ofTmaxafter 1990 when the surface solar radiation stops decreasing in China.

Land surface temperature Ts and near-surface air temperature Ta are two main metrics that reflect climate change. Recently, based on in situ observations, several studies found that Ts warmed much faster than Ta in China, especially after 2000. However, we found abnormal jumps in the Ts time series during 2003–05, mainly caused by the transformation from manual to automatic measurements due to snow cover. We explore the physical mechanism of the differences between automatic and manual observations and develop a model to correct the automatic observations on snowy days in the observed records of Ts. Furthermore, the nonclimatic shifts in the observed Ts were detected and corrected using the RHtest method. After corrections, the warming rates for Ts-max, Ts-min, and Ts-mean were 0.21°, 0.34°, and 0.25°C decade−1, respectively, during the 1960–2014 period. The abnormal jump in the difference between Ts and Ta over China after 2003, which was mentioned in existing studies, was mainly caused by inhomogeneities rather than climate change. Through a combined analysis using reanalyses and CMIP5 models, we found that Ts was consistent with Ta both in terms of interannual variability and long-term trends over China during 1960–2014. The Ts minus Ta (Ts − Ta) trend is from −0.004° to 0.009°C decade−1, accounting for from −3.19% to 5.93% (from −3.09% to 6.39%) of the absolute warming trend of Ts (Ta).

Tight oil reservoirs have poor physical properties, insufficient formation energy, and low natural productivity. CO

With urbanization occurring around weather stations, its impact on the observed air temperature has been widely recognized. However, its assessments were varied partially due to the poor understanding of its underlying mechanism. Here, we analyzed the effect of urbanization using observations obtained from ~2200 weather stations in China from 1960 to 2014. The results showed that the urbanization effect increased from 1960 to 1984 but slowed after 1995 with rapid urbanization in China, particularly in terms of the daily minimum temperature Tmin and daily mean air temperature Tmean. The urbanization effect is nearly linearly related to the urban–rural contrast of effective cloud cover (including the impact of atmospheric aerosols) derived from the observed sunshine duration. Aerosols increase atmospheric downward longwave radiation Ld through their absorption of solar radiation during the daytime, and they trap longwave radiation emitted from the surface during the nighttime. Increased anthropogenic aerosols caused the urban–rural contrast of effective cloud cover to increase from 1960 to 2014. However, the urban–rural contrast of cloud cover remained stable from 1960 to 1984 but substantially decreased due to the “urban dry island effect” after 1995, which compensated for the impact of anthropogenic aerosols on Ld and resulted in a stable urbanization effect after 1995. The urban–rural difference in Ld increased by 0.57 W m−2 (10 yr)−1, which resulted in warming of 0.074°C (10 yr)−1 (78.2%) for Tmin, 0.037°C (10 yr)−1 (151.5%) for Tmax, and 0.056°C (10 yr)−1 (96.6%) for Tmean.

Anthropogenic emissions are generally lower during holidays than they are on workdays, this pattern is expected to result in temperature variations. Variations in the daily maximum (Tmax), mean (Tmean) and minimum (Tmin) air temperatures and the diurnal temperature range (DTR) during the Chinese New Year holiday are evaluated with two methods using daily meteorological observations collected at 2200 stations in China from 1961 to 2015. These two methods yield nearly equivalent results that reflect strong variations in the defined holiday effects. During the period from 1961 to 1980, Tmean, Tmax, Tmin and the DTR all exhibit cooling holiday effects, this effect as measured by the DTR disappears during the period from 1981 to 2000. However, during the period from 2001 to 2015 warming holiday effects are observed for Tmax and the DTR. The evaluation shows that the holiday effect is neither unique nor statistically significant. These results indicate that the holiday effect is primarily caused by natural atmospheric oscillations, because ΔT oscillates noticeably with periods of approximately 7.1 days, 8.5 days and 16.2 days, and these oscillations can account for approximately 75.6% of the variance in ΔT. The oscillation identified here is consistent with the fundamental theory of Rossby wave in the atmosphere.

Diurnal cycle of surface air temperature T is an important metric indicating the feedback of land–atmospheric interaction to global warming, whereas the ability of current reanalyses to reproduce its variation had not been assessed adequately. Here, we evaluate the daily maximum temperature Tmax, daily minimum temperature Tmin, and diurnal temperature range (DTR) in five reanalyses based on observations collected at 2253 weather stations over China. Our results show that the reanalyses reproduce Tmin very well; however, except for Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2), they substantially underestimate Tmax and DTR by 1.21°–6.84°C over China during the period of 1980–2014. MERRA-2 overestimates Tmax and DTR by 0.35° and 0.81°C, which are closest with observation. The reanalyses are skillful in reproducing the interannual variability of Tmax and Tmin but relatively poor for DTR. All reanalyses underestimate the warming trend of Tmin by 0.13°–0.17°C (10 yr)−1 throughout China during 1980–2014, and underestimate the warming trend of Tmax by 0.24°–0.40°C (10 yr)−1 in northwestern China while overestimating this quantity by 0.18°–0.33°C (10 yr)−1 in southeastern China. These trend biases in Tmax and Tmin introduce a positive trend bias in DTR of 0.01°–0.26°C (10 yr)−1 within China, especially in the north China plain and southeastern China. In the five reanalyses, owing to the sensitivity discrepancies and trend biases, the surface solar radiation Rs and precipitation frequency (PF) are notable deviation sources of the diurnal cycle of air temperature, which explain 31.0%–38.7% (31.9%–37.8%) and 9.8%–22.2% (7.4%–15.3%) of the trend bias in Tmax (DTR) over China, respectively.

As the most sensitive and active factor, the quantity, type and diversity of soil microbe in high concentration CO2 are very important problem for ecological impact of leakage risk in CCS projects. The pot experiment in carbon dioxide artificial climate chamber was used to simulate different CO2 concentration (from concentration in normal atmosphere to 80000μmol/mol) of CCS leakage and study the effects of microbial diversity in sorghum rhizosphere soil on elevated CO2. According to comparing the DGGE electrophoresis of bacteria in sorghum rhizosphere soil under different CO2 concentration, five kinds of indicator bacteria were selected when the CO2 concentration was at 10000μmol/mol, and the soil bacteria of sorghum planting can be used as evaluation index of CO2 leakage included Brucella suis, Thiohalocapsahalophil, Burkholderia cepacia, Porphyromonas gingivicanis, and Bacteroides intestinalis. The leakage of the CCS project can be evaluated by the identification of soil bacteria of sorghum planting in the future.

Jingbian CCS Project has being conducted by Shaanxi Yanchang Petroleum Group and Northwest University since January 2012. CO 2 injection was started on September 4, 2012. There are five CO 2 injection wells in Jingbian Field. Till the end of June 2016, more than 60,000 tonnes of CO 2 were injected into Chang 6 reservoir group of Upper Triassic. CO 2 is captured from coal chemical company and transported by truck. CO 2 -EOR is expected to increase oil production in low porosity and extremely low permeability reservoir where water is hard to be injected. Through CO 2 -EOR, the current oil recovery is closing to 10% comparing with water recovery. At the same time, we systematically evaluated the capacity of Chang 6 reservoir. Safety of caprock seal ability and possible fracture distribution are studied as well. 3D reservoir model was made and reservoir simulation was used to evaluate CO 2 migration and predict the CO 2 leakage risk at different CO 2 injection stages. For the surface environmental monitoring, we studied the impact of CO 2 concentration on soil and microorganism, murine and fish was studied so that we might find indirect indicators for CO 2 leakage. Furthermore, 3D seismic baseline data was acquired in the second CCS site of Shaanxi Yanchang Petroleum Group.

The Ordos Basin has the richest natural resources in China. It has over one third of the coal resources of China and it is the second largest oil and natural gas sedimentary basin in China. The Yanchang Petroleum Group is the only company that has both coal and petroleum mineral rights in this basin, which provides a unique favorable condition for implementing a carbon capture utilization and storage (CCUS) project in China. The CCUS project conducted by the Yanchang Petroleum Group integrates a clean coal chemical plant with low-cost carbon dioxide (CO 2 ) capture facilities and CO 2 enhanced oil recovery (EOR) and storage in tight formations. The coal chemical plant produces methanol and acetic acid from coal using the Texaco coal gasification process. High purity CO 2 is separated from the methanol rich solvent. After compression and deep-freezing treatment, liquid CO 2 with a purity of 99% is produced for CO 2 EOR and the storage project. The cost of the CO 2 product is about 117 Renminbi (RMB)/tonne CO 2 , which is less than US $18/tonne of CO 2 . This cost is about half of the cost of CO 2 in the coal power plant (US $30-40/tonne). The captured CO 2 is transported to a CO 2 EOR and storage project about 30–100 km away, which is a much shorter distance than the required transportation distances of other commercial CO 2 EOR and storage projects. For example, the transportation distance is over 300 km for the Weyburn project. The short distances between the CO 2 capture facility and the oil fields further reduce the transportation costs of the CCUS project in China. The oil fields in the Ordos Basin are mainly tight formations with low reservoir pressures. Water resources are very limited in the basin. Thus, minimizing water usage in the petroleum industry can significantly protect the environment in this area. Carbon dioxide EOR can reduce the water usage and enhance oil recovery at the same time. An extensive experimental study was conducted to maximize the performance of CO 2 EOR in tight formations with low reservoir pressures. The current reservoir pressure in those oil fields is less than 10 MPa, which is far lower than the minimum miscible pressure (MMP) (16–22 MPa). Different approaches, such as CO 2 foam flooding and huff-n-puff, have been proposed to build up the reservoir pressure to enhance the oil recovery performance. A field pilot test, containing about 50 wells, has been conducted for four years, and the oil production rates for those wells have been doubled or tripled. This project is the first integrated CCUS project operated in China. Currently seventy thousand tonnes of CO 2 have been injected. In the next five years, this project will be expanded to 1 million tonnes of CO 2 injection, which will make it the second largest CCUS project in the world after Canada’s Weyburn project.

This study compared the diurnal and seasonal cycles of atmospheric and surface urban heat islands (UHIs) based on hourly air temperatures (Ta) collected at 65 out of 262 stations in Beijing and land surface temperature (Ts) derived from Moderate Resolution Imaging Spectroradiometer in the years 2013–2014. We found that the nighttime atmospheric and surface UHIs referenced to rural cropland stations exhibited significant seasonal cycles, with the highest in winter. However, the seasonal variations in the nighttime UHIs referenced to mountainous forest stations were negligible, because mountainous forests have a higher nighttime Ts in winter and a lower nighttime Ta in summer than rural croplands. Daytime surface UHIs showed strong seasonal cycles, with the highest in summer. The daytime atmospheric UHIs exhibited a similar but less seasonal cycle under clear-sky conditions, which was not apparent under cloudy-sky conditions. Atmospheric UHIs in urban parks were higher in daytime. Nighttime atmospheric UHIs are influenced by energy stored in urban materials during daytime and released during nighttime. The stronger anthropogenic heat release in winter causes atmospheric UHIs to increase with time during winter nights, but decrease with time during summer nights. The percentage of impervious surfaces is responsible for 49%–54% of the nighttime atmospheric UHI variability and 31%–38% of the daytime surface UHI variability. However, the nighttime surface UHI was nearly uncorrelated with the percentage of impervious surfaces around the urban stations.

In order to reduce greenhouse gas emissions from coal chemical industry in Northwest China, Yanchang Petroleum has deployed and developed a carbon dioxide capture project at one of its affiliated coal chemical plant in Yulin, Northwest China. The CO2 capture unit was built at a 200,000 t/a coal to acetic acid chemical plant. The CO2 is captured from coal gasification process using a Rectisol process, finally compressed and stored in liquid state with a pressure of 2.3 Mpa and a temperature at -17 ℃. 50,000 t/a of high concentration CO2 (>99%) was captured, and delivered to the Jingbian and Wuqi CCUS pilot sites by truck tanker for CO2-EOR and geological storage projects. The CO2 capture cost is less than 18 USD/t CO2 (

In this paper, we investigated the long-term reclamation-induced ground subsidence in Macao, a coastal city of southern China. Persistent Scatterers Interferometry (PSI) technique was applied to retrieve the deformation rate in Macao during the period from April 2003 to August 2010 with a total of 41 scenes of descending ASAR data sets. The PSI-retrieved results showed a relatively stable pattern in Macao Peninsula, Taipa Island and Coloane Island, with an average subsidence velocity of -3 mm/y. In contrast, relatively large subsidence rates were highlighted in Cotai area, a newly reclamation land in 1990s, in which an average subsidence velocity was about -10 mm/y. A consistent relationship between the PSI results and the leveling measurements indicated that this PSI technique is an effective tool to monitor the reclamation-induced ground subsidence with a high accuracy and adequate spatial details. Accordingly the valuable ground subsidence results generated by PSI can be used not only for early detection and remedial activities of potential settlement of buildings, but also for helping the local government to formulate regional sustainable development planning and decision-making in disaster prevention and mitigation.

In this paper, we designed a set of CO2 gas monitoring system in the CO2 Geological Storage Project which was used in Ordos Basin of western China. The change of CO2 concentration in atmosphere and soil was effected by environmental factors, for example atmospheric temperature, atmospheric pressure, Atmospheric humidity, wind power, soil temperature, soil moisture, etc. The CO2 gas monitoring system was designed to monitor CO2 concentration and key environmental factors. Data transmission technologies were used general packet radio service (GPRS), peanut shell DDNS. The CO2 gas monitoring system in the CO2 geological storage project had a series of capacities to monitoring CO2 gas and environmental parameters. And could been widely used in geological storage projects.

The study of physiological impact on crops are important area of ecological impacts on CO 2 leakage on CCS. Physiological effects of CO 2 to C4 Crops were simulated with CO 2 artificial climate chamber in this paper. The main conclusions are as follows: (1) When CO 2 concentration was less than 20000 μmol/mol, net photosynthetic rate, transpiration rate and stomatal conductance of four C4 crops were increased with the increasing of CO 2 concentration. When CO 2 concentration was higher than 20000 μmol/mol, the three indicators were decreased with the increasing of CO 2 concentration. The indicators of the four C4 crops were reached the maximum values at 20000 μmol/mol of CO 2 concentration and the minimum values at 80000 μmol/mol respectively. The impacts of CO 2 to corn and sorghum were greater than that of millet and broom corn millet. (2) Intercellular CO 2 concentrations of the four C4 crops were increased with increasing of CO 2 concentration, but their growth rates were decreased gradually. (3) With the increase of CO 2 concentration, the leaf temperature of four C4 crops showed the opposite rule with net photosynthetic rate, transpiration rate and stomatal conductance.

CCS is considered to be the most effective way to control the CO 2 emissions. But there is a risk of leakage with CCS projects during the process of actual operation. So, it is important to research the leakage of CCS. In this article, the range of CO 2 concentration which affects the inhibition and promotion of microorganism growth can be determined by analyzing the response of soil microbes in different CO 2 concentrations. The soil microbial indicators of sorghum have a similar trend when the concentration of CO 2 between normal atmosphere and 80000 μmol/mol. It shows a decreasing trend after the first increase. And the indicators reach the maximum at 20000 μmol/mol and the minimum at 80000 μmol/mol respectively. The leakage of the CCS project can be evaluated by analyzing the response of soil microbes in the future.

Jingbian CCS-EOR pilot project is the first full chain CCS-EOR project in China. Sponsored by China Ministry of Science and Technology, Shaanxi Yanchang Petroleum (Group) Co. Ltd started to conduct CO2 capture from its coal chemical company and injected CO2 in Jingbian Field which cooperated with Northwest University from 2012. Our target is to inject at least 10,000 tons CO2 in Jingbian Field of Shaanxi Yanchang Petroleum (Group) Co. Ltd. At the same time, we are developing an integrated MMV (Measurement, Monitoring and Verification) technique to monitor the safety of CO2 sequestration from surface to subsurface by using environmental, geophysical monitoring methods and geological analysis. At this low porosity and low permeability reservoir of Jingbian Field, we planned to inject CO2 in more than 5 wells and tried to get enhanced oil recovery ratio about 5% to 8% and form CO2-EOR techniques and a demonstration pilot project so that we may apply CCS-EOR in Ordos Basin which is the largest oil and gas production basement in China. Jingbian CCS-EOR pilot project is the same as the other CCS projects in the world. It includes site selection, CO2 storage and injection equipment construction, CO2 capture equipment construction, CO2-EOR laboratory tests and MMV study.

Because of the risk of leakage with CCS (Carbon Capture and Sequestration) projects, the near surface ecological impact is considered to be an important area on CCS. In order to research soil impact of CCS, physical-chemical properties of soil were analyzed through the simulation in CO 2 artificial climate chamber. The results showed as follows: Soil particle size distribution and the concentrations of heavy metal have no significant impacts with the elevated of CO 2 concentration. All ionic concentration except HCO 3 - descended slightly at low concentration and increased obviously at high concentration with the elevating of the CO 2 concentration. HCO 3 - and pH had no obvious variation with the change of the CO 2 concentration. AHN, TN, AP, TP and AK of soil had a slightly increasing with the elevating of CO 2 concentration. But AHN/TN, AP/TP had no significant change with the elevating CO 2 concentration.

The first CCS-EOR (Enhanced Oil Recovery) pilot project in Shaanxi Province of China is being conducted. Although there are still many technical obstacles need to be solved, the major concern with this CCS (Carbon Capture and Sequestration) project is the risks of CO2 leaking from the subsurface storage site. While the industry worries about the efficiency of CO2-EOR in such low porosity and ultra- low permeability reservoir. In the present work, we assess the potential risks as well as reservoir properties in CO2 geological storage site in Jingbian Field, North of Shaanxi. We design a comprehensive monitoring system, which covers geophysical, geological and surface environmental monitoring, in order to detect plume behaviour and leakage of CO2 during different stages of CO2 sequestration. The study of monitoring data and CO2-EOR operation in Jingbian CCS pilot project will increase our understanding of underground process during CO2 injection and after site closure in Ordos Basin.