Shanghai is the biggest metropolis in China, and its local temperature change is affected not only by global warming but also by urbanization. Integrating the Mann-Kendall test, EMD (Empirical Mode Decomposition), Cross Wavelet Analysis and statistical methods, we studied the response of the local temperature change in Shanghai to global warming and urbanization. The results indicate that the local temperature at Shanghai present a significant warming trend under the background of global warming over the past 135 years. The local temperature at Shanghai displays 2-year, 6-year, 15-year, 23-year and 68-year periodic fluctuation, whereas global temperature shows 4-year, 9-year, 15-year, 23-year and 68-year cyclic variation. Although the two cycles are not exactly the same, they show some comparability. Urbanization facilitated the warming process of Shanghai. In the most recent 50 years, temperature difference between urban and suburban Shanghai has increased nearly 0.4 • C. The related indicators of urban development, such as population, built-up area, Gross Domestic Product (GDP), energy consumption and number of vehicles show significantly positive correlation with the temperature difference between urban and suburban area. In addition, the frequency of extreme high temperature has become higher, whereas the frequency of extreme low temperature has become lower over the most recent 55 years.

Stabilizing the atmosphere and ventilating the sub-cloud layer through vertical transport of moisture, moist convection is an important sub-grid scale process that still needs to be parameterized in general circulation models (GCMs) in the coming decades (Plant & Yano, 2016). The purpose of convection parameterization is to provide feedback on sub-grid scale convection to the large-scale fields as tendency terms. It is important to keep in mind that for achieving this goal, we do not have to introduce full details of convection into a parameterization. Rather, it must constitute a caricature of the reality of convection, as emphasized by Yano (2014b). Therefore, early convection schemes only considered the feedback without describing the convective clouds (e.g., the moist adjustment scheme of Manabe et al. (1965) or the moisture convergence scheme of Kuo (1965)). However, some shortcomings, including fixed tropical temperature profiles (Arakawa, 2004) and unreasonable convective moistening profiles (Emanuel, 1994), are related to such an oversimplified approach, indicating that an idealized caricature cannot encompass the collective effect of a series of complex processes during the convection. A practical way to mitigate this problem is to describe more basic features of convective clouds in detail in convection schemes. As a result, convection schemes started to adopt a bulk or spectrum mass-flux (plume) formulation (e.g.,

It has been confirmed that the karst rocky desertification (KRD) has severely changed the interactions between atmosphere and terrestrial ecosystem which would cause a significant effect on regional climate system. In this study, the Weather and Research Forecasting model was applied to investigate the biogeophysical impact on temperature and precipitation change by land use/land cover change data with different KRD conditions in 1993KRD conditions in , 2003KRD conditions in , and 2013 in Southwest China. The results showed that an improving trend of KRD has been found in Southwest China, especially in east Sichuan, Chungking, southwest Yunnan, and south Guangxi. The 2-m air temperature decreased by 0~− 1°C in general with this improving trend. The possible reason was the decreasing KRD accompanied by the decreasing albedo, causing the increasing net shortwave radiation and the increasing net radiation. Meanwhile, the increasing evaporation strengthened the latent heat flux and weakened the sensible heat flux so that decreased temperature was addressed in forest areas. The effect of KRD change transferred to the upper troposphere through atmosphere vertical convection, which made the subtropical high to be strengthened and westerly extended. Therefore, the upward moisture flux at the surface (QFX) was weakened in the central part of Guangxi, southern Guizhou, which led to the decrease of the precipitation. Moreover, the southwest monsoon was strengthened, which caused the increasing water vapor flux and led to the heavy rainfall in the west of Yunnan.

Performance of global climate models (GCMs) is strongly affected by their cumulus parameterizations (CP) used. Similar to the approach in GFDL AM4, a double-plume CP, which unifies the deep and shallow convection in one framework, is implemented and tested in NCAR Community Atmospheric Model version 5 (CAM5). Based on the University of Washington (UW) shallow convection scheme, an additional plume was added to represent the deep convection. The shallow and deep plumes share the same cloud model, but use different triggers, fractional mixing rates and closures. The scheme was tested in single column, short-term hindcast and AMIP simulations. Compared with the default combination of Zhang-McFarlane scheme and UW scheme in CAM5, the new scheme tends to produce a top-heavy mass flux profile during the active monsoon period in the single column simulations. The scheme increases the intensity of tropical precipitation, closer to TRMM observations. The new scheme increased subtropical marine boundary layer clouds and high clouds over the deep tropics, both in better agreement with observations. Sensitivity tests indicate that regime dependent fractional entrainment rates of the deep plume are desired to improve tropical precipitation distribution and upper troposphere temperature. This study suggests that a double-plume approach is a promising way to combine shallow and deep convections in a unified framework.

General circulation models (GCMs) are widely used for global weather forecasting and climate modeling. In a GCM, the convective parameterization, which represents the bulk effects of convection, is typically regarded as a large source of model uncertainty (Arakawa, 2004;Rybka & Tost, 2014;Tost et al., 2006). Cumulus convection interacts with other processes in complex ways. Heat and moisture are pumped out of the planetary boundary layer (PBL) by subgrid-scale cumulus cells in response to surface solar heating. Detrainment and/or re-evaporation from convective condensate and precipitation moisten the grid-scale environment, favoring large-scale condensation. Convective parameterizations also strongly regulate the partition of convective and large-scale precipitation over the tropics with resultant effects on clouds and tropical transients (Kim et al., 2012;Lin et al., 2013). The interdependency between subgrid-and grid-scale processes further influences the hydrological processes, cloud types, and thus cloud radiative forcing and its feedback (Arakawa, 2004;Hourdin et al., 2006).Apart from the mean states, the impact of convective parameterization on tropical variabilities has also been reported in some previous studies (

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Concrete with light weight and pervious performance has been widely recognized as an effective and sustainable solution for reducing the negative impacts of urbanization on the environment, as it plays a positive role in urban road drainage, alleviating the urban heat island effect and thermal insulation, as well as seismic performance, etc. This research paper presents a feasibility study of pervious concrete preparation with ceramsite as aggregate. First, pervious concrete specimens with different types of aggregates at various water–cement ratios were prepared, and the mechanical properties of pervious concrete specimens were evaluated based on the compressive strength test. Then, the permeability properties of the pervious concrete specimens with different types of aggregates at various water–cement ratios were characterized. Meanwhile, statistical analysis and regression fitting were conducted. Finally, the analysis of the freeze–thaw durability of pervious concrete specimens with ceramsite as aggregate according to indexes including quality loss rate and strength loss rate was performed. The results show that as the water–cement ratio increased, the compressive strength and permeability coefficient of pervious concrete generally decreased. Compressive strength and permeability coefficient showed a great correlation with the water–cement ratio; the R2 values of the models were around 0.94 and 0.9, showing good regression. Compressive strength was mainly provided by the strength of the aggregates, with high-strength clay ceramsite having the highest 28-day compressive strength value, followed by ordinary crushed-stone aggregates and lightweight ceramsite. Porosity was mainly influenced by the particle size and shape of the aggregates. Lightweight ceramsite had the highest permeability coefficient among different types of cement-bound aggregates, followed by high-strength clay ceramsite and ordinary crushed-stone aggregates. The quality and compressive strength of pervious concrete specimens decreased with the increase in freeze–thaw cycles; the quality loss was 1.52%, and the compressive strength loss rate was 6.84% after 25 freeze–thaw cycles. Quadratic polynomial regression analysis was used to quantify the relationship of durability and freeze–thaw cycles, with R2 of around 0.98. The results provide valuable insights into the potential applications and benefits of using ceramsite as an aggregate material in pervious concrete for more sustainable and durable infrastructure projects.

The safety and reliability of bridges gradually decrease over time under the influence of disadvantageous environmental factors, primarily due to reinforcement corrosion caused by chloride ingress. The traditional lateral load distribution (LLD) theory does not consider the influence of corrosion, which degrades the accuracy of bridge performance and reliability calculation. A time-dependent reliability assessment method for simply supported T-beam bridges is proposed in this paper, which considers the influence of reinforcement corrosion on LLD. Firstly, the steel corrosion process and degree are predicted based on the chloride ingress model, into which the water/cement ratio and concrete strength are innovatively introduced in order to improve the prediction accuracy. Secondly, the effective stiffness calculation method for corroded reinforcement bridges is established with the moment of inertia and section crack condition employed. Thirdly, the modified eccentric compression method is improved by the effective stiffness and iterative algorithm, which is suitable for the LLD calculation of corroded reinforcement bridges. The time-dependent vehicle load effect can be computed combined with the probability distribution of live load. Finally, the time-dependent reliability of the flexural bearing capacity is obtained by the Monte Carlo method and Bayesian theory without prior information. A simply supported bridge with five T-beams is taken as an example for analysis. It is indicated that the results calculated by the traditional reliability method are conservative, which cannot make a true and accurate evaluation. The method proposed in this paper can effectively reduce the assessment error caused by model uncertainty while considering the interaction between reinforcement corrosion and vehicle live load effect.