A case study of the MJO event observed during January and February 2017 is conducted to understand its propagation through the Maritime Continent (MC) region. Ensemble cloud-permitting numerical simulations are performed to test the effects of the islands over MC on this MJO event. The control simulation reasonably captures the large-scale mean state, eastward propagation and diurnal cycle over islands

Instrumental records suggest multidecadal variability in Arctic surface temperature throughout the twentieth century. This variability is caused by a combination of external forcing and internal variability, but their relative importance remains unclear. Since the early twentieth century Arctic warming has been linked to decadal variability in the Pacific, we hypothesize that the Pacific could impact

The Canary current upwelling is one of the major eastern boundary coastal upwelling systems in the world, bearing a high productive ecosystem and commercially important fisheries. The Canary current upwelling system (CCUS) has a large latitudinal extension, usually divided into upwelling zones with different characteristics. Eddies, filaments and other mesoscale processes are known to have an impact

As global warming gets worse, the extreme heat exposure time is expected to increase. Considering that the heatwave damages increased by the accumulation of heat stress, it is important to understand the heatwave onset and number of heatwave days (HWDs). Here, we show that the end of East Asian summer monsoon activity (i.e., Changma retreat date, CRD) could be an indicator in determining the onset

The Earth climate system has an intrinsic mechanism to maintain its energy conservation by impelling opposite changes in meridional ocean and atmosphere heat transports. This mechanism is briefed as the Bjerknes compensation (BJC). We set up a global coupled two-hemisphere box model in this study, and obtain an analytical solution to the BJC of this system. In the two-hemisphere model, the thermohaline

Following a high-end projection for mass loss from the Greenland and Antarctic ice-sheets, a freshwater forcing was applied to the ocean surface in the coupled climate model EC-Earthv2.2 to study the response to meltwater release assuming an RCP8.5 emission scenario. The meltwater forcing results in an overall freshening of the Atlantic that is dominated by advective changes, strongly enhancing the

Recent studies emphasize the significance of precipitation characteristics at intraseasonal time scales for better predicting the monsoonal rainfall. In this connection, to understand the differences in characteristics of the vertical structure of precipitation during wet and dry spells over the Arabian Sea (AS) and Bay of Bengal (BOB) from the southwest monsoon (SWM) to northeast monsoon (NEM) using

Understanding future drought risks plays a crucial role in developing climate change adaptation strategies and in enhancing disaster resilience. However, previous studies may lead to biased conclusions due to the neglect of two factors, including the relative performance of climate simulations and the uncertainty in drought characterization. In this study, Bayesian model averaging is used to merge

Climatologically, the frequency of tropical cyclones (TCs) in the Bay of Bengal (BoB) is higher relative to that over the Arabian Sea (ARB). However, recent years exhibit a greater number of TCs forming in the ARB than in the BoB. During the study period (1982–2019), a significant increasing trend in the intensity, frequency, and duration of cyclonic storms (CS) and very severe CS (VSCS) is observed

The aim of this work is a comprehensive study of the 16-year periodicity of winter surface temperature in the Antarctic Peninsula (AP) region, described earlier, and its possible source based on weather station records over the 1952–2019 period making use of the Scientific Committee on Antarctic Research (SCAR) Reference Antarctic Data for Environmental Research (READER) database, as well as Fourier

Interannual oscillatory modes, atmospheric and oceanic, are present in several large regions of the globe. We examine here low-frequency variability (LFV) over the entire globe in the Community Earth System Model (CESM) and in the NCEP-NCAR and ECMWF ERA5 reanalyses. Multichannel singular spectrum analysis (MSSA) is applied to these three datasets. In the fully coupled CESM1.1 model, with its resolution

Intense cyclones have become more frequent over the North Indian Ocean (NIO) region causing significant risk and vulnerability to the coastal regions. Analysis clearly revealed an increasing trend (~ 16.75%) in the intensity of severe cyclonic storms that formed over the NIO during the past 4 decades. Power dissipation index (PDI) showed a correlation of 0.58 with severe cyclonic storms during the

The drivers of precipitation variability in the Ethiopian Highlands are complex, and they have considerable impact on the local rural economy of the region. While interannual variability has been studied extensively, relatively less study has focused on intra-seasonal variability in precipitation, even though this variability can be critical for agricultural activities. In this study, we examine the

The West Antarctic climate has witnessed large changes during the second half of the twentieth century including a strong and widespread continental warming, important regional changes in sea-ice extent and snow accumulation, as well as a major mass loss from the melting of some ice shelves. However, the potential links between those observed changes are still unclear and instrumental data do not allow

The western North Pacific anticyclone (WNPAC) is the key bridge that connects El Niño to the East Asian climate anomalies. The persistence and breakdown of the WNPAC has important implications for climate prediction. Our results show that the eastern Pacific (EP) El Niño-induced WNPAC has good persistence in spring, whereas the central Pacific (CP) El Niño-induced WNPAC has an obvious breakdown in

Strong offshore wind events (SOWEs) occur frequently near the Antarctic coast during austral winter. These wind events are typically associated with passage of synoptic- or meso-scale cyclones, which interact with the katabatic wind field and affect sea ice and oceanic processes in coastal polynyas. Based on numerical simulations from the coupled Finite Element Sea-ice Ocean Model (FESOM) driven by

Land surface processes are vital to the performance of regional climate models in dynamic downscaling application. In this study, we investigate the sensitivity of the simulation by using the weather research and forecasting (WRF) model at 10-km resolution to the land surface schemes over Central Asia. The WRF model was run for 19 summers from 2000 to 2018 configured with four different land surface

Observed surface warming trends over the Arabian Peninsula are a factor of 1.4–2.1 greater than the tropical mean and a factor of 2.3–3.1 greater than the global mean. The primary reason for the amplified warming is the absence of latent cooling over the dry surface, not trends in net longwave heating or solar fluxes. Well-validated regional model simulations with 30-km resolution are used to evaluate

Multiple oceanic eddies coexist in the North Pacific subtropical front zone (STFZ) in winter, which can be classified into the isolated single eddies, the combined double isotropic eddies and pairs of anisotropic eddies. The forcings of these eddies on the mid-latitude atmosphere are investigated using Climate Forecast System Reanalysis (CFSR) data from year 1979 to 2009, which are divided into the

Future projections in austral winter characteristics of explosive extratropical cyclones (EECs) in three CORDEX Southern Hemisphere domains (Africa-AFR, Australia-AUS and South America-SAM) are investigated. The projections are obtained with a fine resolution (25 km) Regional Climate Model (RegCM4) within the CORDEX-CORE framework driven by three Global Climate Models (GCMs: HadGEM2-ES, MPI-ESM-MR

In this study we present a diagnostic model for the large-scale tropical circulation (vertical motion) based on the moist static energy equation for first baroclinic mode anomalies (MSEB model). The aim of this model is to provide a basis for conceptual understanding of the drivers of the large-scale tropical circulation changes or variations as they are observed or simulated in Coupled Model Inter-comparison

The purpose of this study is to analyze the dynamic/thermodynamic features of the center and periphery of upper tropospheric cyclonic vortices (UTCV) in Northeast Brazil (NEB). An algorithm was developed to identify the vortex climatology using ERA-Interim, while rainfall impact was assessed using the Climate Prediction Center dataset, from 1980 to 2016. The algorithm was validated by comparison UTCV’s

Tropical cyclones (TCs) are one of the most destructive natural hazards that pose a serious threat to society, particularly to those in the coastal regions. In this work, we study the temporal evolution of the regional weather conditions in relation to the occurrence of TCs using climate networks. Climate networks encode the interactions among climate variables at different locations on the Earth’s

Bangladesh stands out as a climate change hot spot due to its unique geography, climate, high population density, and limited adaptation capacity. Mounting evidence suggests that the country is already suffering from the effects of climate change which may get worse without aggressive action. Here, we use an ensemble of high-resolution (10 km) regional climate model simulations to project near-term

Model simulations are highly sensitive to the formulation of the atmospheric mixing process or entrainment in the deep convective parameterizations used in their atmospheric component. In this paper, we have implemented stochastic entrainment in the deep convection scheme of NCAR CAM5 and analyzed the improvements in model simulation, focusing on the South Asian Summer Monsoon (SASM), as compared to

Using the prediction data from the Global Seasonal Forecast version 5 (GloSea5) during the 1993–2016 period, the probabilistic prediction skills of the midsummer (July and August) surface air temperature (SAT) over the middle and lower reach of the Yangtze River valley (MLYR) are evaluated by the ranked probabilistic skill score. We found that the GloSea5 better predicts below-normal (BN) events than

Southwest China (SWC) is located in the transition zone affected by the East Asia summer monsoons, India monsoon, and the Tibetan Plateau thermal activity. SWC is also an important hub for water vapor transport in the Asia–Pacific (AP) region. Here we study the dynamical and spatiotemporal characteristics of extreme rainfall events in AP by a synchronization network approach, providing insights for

Decadal Climate Predictions (DCP) have gained considerable attention for their potential utility in promoting optimised plans of adaptation to climate change and variability. Their effective applicability to a targeted problem is nevertheless conditional on a detailed evaluation of their ability to simulate the near-term climate evolution under specific conditions. Here we explore the performance of

Changes in the freeze–thaw cycles of shallow soil have important consequences for surface and subsurface hydrology, land–atmosphere energy and moisture interaction, carbon exchange, and ecosystem diversity and productivity. This work examines the shallow soil freeze–thaw cycle on the Tibetan Plateau (TP) using in–situ soil temperature observations in 0–20 cm soil layer during July 1982–June 2017. The

Dynamical prediction of monsoon rainfall has been an important topic and a long-standing issue in both research and operational community. This paper provides a comprehensive evaluation of the subseasonal-to-seasonal (S2S) prediction skill of the East Asian summer monsoon (EASM) rainfall using the hindcast record from the Beijing Climate Center Climate System Model, BCC CSM1.1m, during the period 1983–2019

The circumglobal teleconnection (CGT) is an important mode of circulation variability, with an influence across many parts of the northern hemisphere. Here, we examine the excitation mechanisms of the CGT in the ECMWF seasonal forecast model, and the relationship between the Indian summer monsoon (ISM), the CGT and the extratropical northern hemisphere circulation. Results from relaxation experiments

Predictability of Ethiopian Kiremt rainfall (June to September: JJAS) and forecast skill of the European Centre for Medium-Range Weather Forecasts (ECMWF) fifth-generation seasonal forecast system 5 (SEAS5) is explored during 1981–2019. The first empirical orthogonal function of observed rainfall explains 50.6% of the total variability and is characterized by positive rainfall anomalies largely confined

Three-dimensional (3D) planetary wave analysis can provide more regionalized information on stratospheric-tropospheric dynamic interactions. The upward wave flux from the troposphere to the stratosphere is maximized above northeastern Eurasia, while the downward flux occurs mainly over the North America and North Atlantic (NANA) region, which is much stronger during mid-to-late winter. This distribution

Models participating in the North American Multi Model Ensemble project were calibrated and combined to produce reliable precipitation probabilistic forecast over South America. Ensemble Regression method (EREG) was chosen as it is computationally affordable and uses all the information from the ensemble. Two different approaches based on EREG were applied to combine forecasts while different ways

Recent studies point to the sensitivity of mid-latitude winter climate to Arctic sea ice variability. However, there remain contradictory results in terms of character and timing of Northern Hemisphere large-scale circulation features to Arctic sea ice changes. This study assesses the impact of realistic late autumn eastern Arctic sea ice anomalies on atmospheric wintertime circulation at mid-latitudes

Arctic sea ice has been declining over past several decades with the largest ice loss occurring in summer. This implies a strengthening of the sea ice seasonal cycle. Here, we examine global ocean salinity response to such changes of Arctic sea ice using simulations wherein we impose a radiative heat imbalance at the sea ice surface, inducing a sea ice decline comparable to the observed. The imposed

In a recent paper, Baño-Medina et al. (Configuration and Intercomparison of deep learning neural models for statistical downscaling. preprint, 2019) assessed the suitability of deep convolutional neural networks (CNNs) for downscaling of temperature and precipitation over Europe using large-scale ‘perfect’ reanalysis predictors. They compared the results provided by CNNs with those obtained from a

The urban heat island is a representative urban climate characteristic, which can affect heat-stress conditions and extreme precipitation that are closely connected with human life. Better understanding of urban-climate interactions, therefore, is crucial to ultimately support better planning and adaptation in various application fields. This study assesses urban-climate interactions during summer

Accurate description of sea ice velocity is necessary for improving the reproduction and prediction of high-latitude climate in modeling studies. In order to improve the simulated sea ice velocity field based on satellite-derived daily data, a set of sea ice dynamic parameters of the ocean–sea ice model was optimized with a Green’s function method, which uses linear combination of forward sensitivity

Unlike other tropical ocean basins, the Bay of Bengal (BoB) has two tropical cyclone (TC) seasons: a pre-monsoon season (Pre-MS) and a post-monsoon season (Post-MS). More interestingly, during the period from 1981 to 2016, the global maximum and minimum formation rates of super cyclones (SCs, categories 4 and 5) occurred in the Pre-MS and Post-MS, respectively, in the BoB. Methods including Butterworth

Lightning climate change projections show large uncertainties caused by limited empirical knowledge and strong assumptions inherent to coarse-grid climate modeling. This study addresses the latter issue by implementing and applying the lightning potential index parameterization (LPI) into a fine-grid convection-permitting regional climate model (CPM). This setup takes advantage of the explicit representation

The seasonal prediction skills in the CAMS-CSM (the acronym stands for the Chinese Academy of Meteorological Sciences Climate System Model) climate forecast system is evaluated with a set of retrospective forecast experiments during the period of 1981–2019. The CAMS-CSM, which has been registered for the sixth phase of the coupled model intercomparison project (CMIP6), is an atmosphere–ocean–land–sea

The impacts of the low level jets that form through the gaps in the topography in the Limpopo and Zambezi River Valleys (LRV and ZRV) on southern African climate are investigated. ERA-5 reanalysis data and numerical experiments using regional climate models reveal that the two valleys act as main gateways for southwest Indian Ocean-sourced moisture inflows into southern Africa. The effects of the LRV

The African easterly jet (AEJ) and African easterly waves (AEWs) can have both local and far-reaching impacts on weather. It is therefore crucial to understand how the AEJ and AEWs will respond to future climate change. In this study, we examine anthropogenic influences on the AEJ–AEW system using the Weather Research and Forecasting (WRF) model configured as a tropical channel model (TCM). Hindcast

Under the influence of global warming, heatwaves are becoming a major threat in many parts of the world, affecting human health and mortality, food security, forest fires, biodiversity, energy consumption, as well as the production and transportation networks. Seasonal forecasting is a promising tool to help mitigate these impacts on society. Previous studies have highlighted some predictive capacity

The impact of El Niño-Southern Oscillation (ENSO) on the late-winter extra-tropical stratosphere (January–March) is assessed in a multi-model framework. Three state-of-the-art atmospheric models are run with prescribed SST anomalies representative of a strong ENSO event, with symmetric patterns for El Niño and La Niña. The well-known temperature perturbation in the lower stratosphere during El Niño

The representation of ocean heat uptake in Simple Climate Models used for policy advice on climate change mitigation strategies is often based on variants of the one-dimensional Vertical Advection/Diffusion equation (VAD) for some averaged form of potential temperature. In such models, the effective advection and turbulent diffusion are usually tuned to emulate the behaviour of a given target climate

The Tibetan Plateau (TP) plays an important role in regulating the global hydrologic cycle. Using a fully coupled climate model, we conduct sensitivity experiments to quantify the impact of the TP on North Africa precipitation. Removing the TP in the model can enhance North African precipitation. Specifically, North Africa precipitation increases substantially during the rainy season (from May to October)

This study investigated the relationship between East Siberian-Chukchi-Beaufort (EsCB) sea ice concentration (SIC) anomaly in the early autumn (September–October, SO) and northern Eurasian surface temperature (Ts) variability in the early spring (March–April, MA). Results reveal that the early autumn sea ice decrease in the EsCB Seas excites an Arctic anticyclonic anomaly in the lower troposphere in

The interannual variability of precipitation during the summer monsoon transition over the Indochina Peninsula (ICP) is substantially influenced by the sea surface temperature anomalies (SSTAs) of the tropical ocean, showing a robust relationship between April and May (AM) precipitation and the El Niño/Southern Oscillation (ENSO) phenomenon. Dynamic composites and statistical analyses supported by

Past versions of the vulnerability indices have shown the ability to detect susceptible regions by assessing climatic and socioeconomic parameters at local scales. These parameters significantly vary over geographic regions, therefore such an index may not be suitable to identify and predict susceptibility over a large domain. The present endeavour aims to develop a new vulnerablity index that identifies

The Indian Ocean Dipole (IOD) is one of the major climate modes in the tropical Indian Ocean (TIO), influencing the surrounding climate and society. Under anthropogenic warming, the IOD is modulated by the changes in the ocean–atmosphere coupling in the TIO. This study focuses on the IOD seasonal phase locking, which means that the IOD usually peaks in boreal autumn. Based on high-emission scenario

Surface latent heat flux (LHF) is an important component in the heat exchange between the ocean and atmosphere over the tropical western North Pacific (WNP). The present study investigates the factors of seasonal mean LHF variations in boreal summer over the tropical WNP. Seasonal mean LHF is separated into two parts that are associated with low-frequency (> 90-day) and high-frequency (≤ 90-day) atmospheric

Quantifying ecological memory could be done at several levels from the rate of physiological changes in an ecosystem all the way down to responses at the genetic level. One way of unlocking the information encoded in a collective environmental memory is to examine the recorded time-series data generated by different components of an ecosystem. In this paper, we probe into the case of the Great Barrier

Modeling of large rainfall events plays an important role in water resources and floodplain management. Rainfall is resulted from complex interactions between climate factors (air moisture, temperature, wind speed, etc.) and land surface (topography, soil, land cover, etc.). Therefore, deriving accurate areal rainfall is not only relied on atmospheric boundary conditions, but also on the reliability

Previous modelling and observational studies have shown discrepancies in the interannual relationship of winter surface air temperature (SAT) between Arctic and East Asia, stimulating the debate about whether Arctic change can influence midlatitude climate. This study uses two sets of coordinated experiments (EXP1 and EXP2) from six different atmospheric general circulation models. Both EXP1 and EXP2

The temperature and moisture distribution over the Indian subcontinent are changing in recent decades with the accelerated global temperature rise. These changes in distribution result in shifting wet/dry and warm/cold zones within India. The differential warming rate over land and surrounding ocean determine intricate dynamics of the Indian summer monsoon (ISM) and make the Indian region a more susceptible

Land-surface temperature changes lead to thermal contrasts between the land and the sea and have significant water cycle impacts particularly within global monsoon regions. Whilst such influence may dominate in the East Asian summer monsoon region, the long-term warm-season temperature dynamics in monsoonal China have not been effectively explored. Here, an annually resolved maximum latewood density

Previous studies indicated that boreal spring North Atlantic horseshoe-like (NAH) sea surface temperature (SST) anomaly pattern has a significant impact on the surface air temperature (SAT) variation over the mid-high latitudes of Eurasia via an atmospheric wave train. This study investigates the connection of springtime NAH SST anomaly and the Eurasian SAT variation in thirty-two coupled climate models

Land surface and atmosphere are interlocked by the hydrological and energy cycles and the effects of soil water-air coupling can modulate near-surface temperatures. In this work, three paired experiments were designed to evaluate impacts of different soil moisture initial and boundary conditions on summer temperatures in the Mediterranean transitional climate regime region. In this area, evapotranspiration