Under the global warming, the influence of increased CO2 on regional climate change is driven by two main effects: CO2 direct radiation and oceanic warming. Based on the outputs of CMIP5 (phase 5 of the Coupled Model Intercomparison Project), the present study found that CO2 direct radiation and uniform oceanic warming are mainly responsible for the heat source (HS) enhancement led by increased CO2

Projected changes in near-surface relative humidity (RH) remain highly model-dependent over land and may have been underestimated by the former generation global climate models. Here the focus in on the recent CNRM-CM6-1 model, which shows an enhanced land surface drying in response to quadrupled atmospheric CO2 compared to its CNRM-CM5 predecessor. Atmosphere-only experiments with prescribed sea surface

In the present study, the Max-Planck-Institute for Meteorology’s Earth System Model is used to investigate irrigation’s general effect on severe and extreme hydrometeorological regimes. Our idealized simulations show a large potential to modulate the magnitude and occurrence frequency of severe and extreme precipitation rates, indicating the possibility to mitigate some of the detrimental effects of

The El Niño Southern Oscillation (ENSO) is an important coupled ocean–atmosphere phenomenon in the tropical Pacific and an important modulator of the spatio-temporal variability of Indian summer monsoon rainfall (ISMR). Here, we explore the impact of ENSO during onset (June), peak (July–August) and withdrawal (September) phases of ISMR for the period 1951–2015, by studying the changes in the ENSO-monsoon

In the original publication of the article, there is a three slashes in Fig. 1.

Sensitive parameters of a numerical weather prediction model substantially influence the model prediction. Weather research and forecasting (WRF) model parameters are assigned default values based on theoretical and experimental analysis by the scheme developers. Calibrating the sensitive parameters of the model has the potential to improve model prediction. The objective of this study is to improve

A large uncertainty exists today in quantifying the absorbing aerosol snow darkening effect (SnoDE) and its relative role compared to the direct radiative effect (DRE), especially at the regional scale. Using a regional climate model over an enlarged South Asia Coordinated Regional Climate Downscaling Experiment (CORDEX) domain, here we isolate these effects and examine their impacts on the dynamics

The ERA5 reanalysis product has been compared with hourly near-surface wind speed and gust observations across Sweden for 2013–2017. ERA5 shows closer agreement than the previous ERA-Interim reanalysis with regard to both mean wind speed and gust measurements, although significant discrepancies are still found for inland and mountainous regions. Therefore, attempts have been made to improve formulations

A key contribution to the latest generation of climate projections for the UK (UKCP18) was a perturbed parameter ensemble (PPE) of global coupled models based on HadGEM3-GC3.05. Together with 13 CMIP5 simulations, this PPE provides users with a dataset that samples modelling uncertainty and is ideal for use in impacts studies. Evaluations of global mean surface temperatures for this PPE have shown

Anthropogenic climate change is expected to strengthen upwelling events worldwide, driven by an increase of upwelling-favorable winds. However, Earth System Models (ESM) tend to underestimate regional processes due to their coarse grid resolution, which can lead to local biases. We use a high-resolution ocean model (\({1/12}^{\circ }\)) forced by results from the Max-Planck-Institute-ESM to analyze

The interdecadal enhancement in the interannual variability of summer monsoon meridional circulation (SMMC) over the South China Sea around the early 1990s is investigated. Results show the change in the SMMC variability may arise from the interdecadal shift in the leading modes of low-level geopotential height over East Asia–Australia and Indo–Pacific sea surface temperature anomalies (SSTAs) in boreal

The Atlantic Meridional Overturning Circulation (AMOC) is a main driver for predictability at decadal time scales, but has been largely ignored in the context of seasonal forecasts. Here, we show compelling evidence that AMOC initialization can have a direct and strong impact on seasonal forecasts. Winter reforecasts with SEAS5, the current operational seasonal forecasting system by the European Centre

The interannual variability of the northern northeast Brazil (NNB) rainfall is directly affected by the dynamics of large-scale systems through atmospheric circulation. In this context, a hidden Markov model (HMM) was used to describe the daily rainfall occurrence and intensity at four meteorological stations of the Metropolitan Region of Fortaleza (MRF) in the NNB, and the global teleconnection patterns

The evolution of the Indian Summer Monsoon (ISM) has been widely investigated and traditionally interpreted as consequences of orbital forcing change and the migration of the Intertropical Convergent Zone (ITCZ). The potential influence of sea-surface temperature (SST) on ISM variation at millennial time scales has been progressively proposed in recent studies. Towards a better understanding of Holocene

The precipitation behaviour at different timescales (interannual, intraseasonal and synoptic) and extreme events in a warmer scenario over South America is analysed. This study is based on a set of Regional Climate Models (RCM) from the CORDEX database and their driving Global Climate Models (GCM) from the CMIP5 Project. Historical simulations for 1979–2005 and from the RCP4.5 scenario for 2071–2100

The dates of the transition between winter and summer (W2S) and between summer and winter (S2W) regional-scale atmospheric regimes have been defined using daily weather types above and around the Caribbean basin from 1979 to 2017. The uncertainties due to either the use of two different reanalyses (i.e., NCEP-DOE and ERA-Interim) or the parametrization used for the definition of the transition dates

This study investigates how teleconnections linking tropical rainfall anomalies and wintertime circulation in the northern extra-tropics are represented in historical simulations for the period 1950–2010 run by partners of the EU-funded PRIMAVERA project, following the HighResMIP protocol of CMIP6. The analysis focusses on teleconnections from the western/central Indian Ocean in mid-winter and from

The frequency and intensity of extreme hydrological events (droughts and floods) have been increasing over the past few decades, which has been posing a threat to water security and agriculture production. Thus, projecting the future evolution of hydrological extremes plays a crucial role in sustainable water management and agriculture development in a changing climate. In this study, we develop the

This study investigates the influences of internal climate variability (ICV) on Eurasian spring (March–May) surface air temperature (SAT) trends based on a 30-member ensemble of the Community Earth System Model version 1 (CESM1) from 1979 to 2014. The SAT trends over the mid-high latitude Eurasia vary considerably among individual simulations, indicating a large impact of ICV on SAT trends at regional

Extraordinarily frequent and long-lasting snowstorms affected China in January 2008, causing extensive social and economic damages. The potential predictability of such extreme events on the sub-seasonal timescale has been evaluated using results from the hindcast experiments by the Beijing Climate Center Climate System Model. The spatial distribution of precipitation during the period can be successfully

How much and fast the Earth is warming in response to increasing greenhouse gas concentrations is one of the fundamental questions in climate science. Here we investigate the role that different modes of climate variability play in modulating the temperature response. We show evidence for a robust statistical relationship between global warming rate variations and Atlantic Multidecadal Variability

The first EOF mode (EOF1) of summer storm track activity over the North Atlantic is characterized by a dipole structure, with negative storm track anomalies over the south coast of Greenland extending northeast across Iceland to the Norwegian Sea and positive anomalies over coastal western Europe. This study shows that a significant interdecadal change in the North Atlantic storm track during boreal

Convection-permitting climate models have shown superior performance in simulating important aspects of the precipitation climate including extremes and also to give partly different climate change signals compared to coarser-scale models. Here, we present the first long-term (1998–2018) simulation with a regional convection-permitting climate model for Fenno-Scandinavia. We use the HARMONIE-Climate

Recent studies suggest that the wintertime North Pacific eddy-driven jet stream will strengthen and extend eastward in response to Arctic sea ice loss. Using output from the Polar Amplification Model Intercomparison Project we examine the mean change of the North Pacific wintertime zonal winds, and use cluster analysis to explore the change in sub-seasonal, wintertime variability in zonal winds between

Increasing precipitation on the Antarctic Ice Sheet (AIS) in a warming climate has the potential to partially mitigate Antarctica’s contribution to sea level rise. We show that a simple, physically motivated change to the shallow convective cloud phase in the Community Earth System Model (CESM)—improving a long-standing bias in shortwave cloud forcing over the Southern Ocean—leads to an enhanced response

We examine the weakening of the Atlantic Meridional Overturning Circulation (AMOC) in response to increasing CO\(_2\) at different horizontal resolutions in a state-of-the-art climate model and in a small ensemble of models with differing resolutions. There is a strong influence of the ocean mean state on the AMOC weakening: models with a more saline western subpolar gyre have a greater formation of

The semi-arid African Sahel region is highly sensitive to changes in monsoon precipitation, as much of the region’s workforce is employed in the agricultural industry (Hamro-Drotz and Programme 2011). Thus, studying the response of rainfall and aridity in this region to radiative perturbations is a matter of pressing humanitarian relevance. In addition, there is evidence to suggest that spatially asymmetric

Ozone in the upper troposphere–lower stratosphere (UTLS) is primarily regulated by tropospheric dynamics. Understanding mechanisms driving ozone variability at the UTLS is crucial to evaluate the transport of mass to and from the lower stratosphere. The El Niño-Southern Oscillation (ENSO) is the primary coupled mode acting on interannual timescales modulating tropospheric circulation worldwide. ENSO

Monsoon intra-seasonal oscillation (MISO) represents a quasi-periodic occurrence of rainfall spells over India during summer monsoon (June–September) associated with large-scale circulation and convection. The connection of MISO with the hydrological cycle has been explored in this study through stable oxygen (δ18O) and hydrogen isotope ratios (δD) in rainwater samples collected from two stations located

A large parameter-perturbed ensemble (PPE) of the Met Office climate model is used to explore the relationship between radiative feedbacks and the present-day simulation of the associated physical processes. We highlight three tropical regimes (deep convection over ocean and land, and marine stratocumulus) in which the same set of processes drives the present-day simulation of clouds and their feedbacks

The rate of warming of the Arctic surface temperature has exceeded that of the global surface temperature in recent decades. However, the underlying process and causes of the long-term warming remain uncertain. In this paper, we explored the factors underlying variation in Arctic mean surface temperature anomalies (AMTA) using a piecewise linear model for 1920–2018. This analysis indicated that the

For the first time, we analyze 2.2 km UK Met Office Unified Model convection-permitting model (CPM) projections for a pan-European domain. These new simulations represent a major increase in domain size, allowing us to examine the benefits of CPMs across a range of European climates. We find a change to the seasonality of extreme precipitation with warming. In particular, there is a relatively muted

The response of the North Pacific storm track to the mesoscale sea surface temperature (SST) in winter is investigated via a global high-resolution atmospheric model. A simulation forced by eddy-resolving SST is compared with a simulation in which the mesoscale SST is filtered out. The results show that removing the mesoscale SST could greatly influence the storm track in the free atmosphere, with

In response to the high demand for more skillful climate forecasts at the seasonal timescale, innovative climate prediction systems are developed with improved physics and increased spatial resolution. Alongside the model development process, seasonal predictions need to be evaluated on past years to provide robust information on the forecast performance. This work presents the quality assessment of

Moisture sources and pathways over the Limpopo River Basin (LRB) in southern Africa were identified using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model applied to NCEP II (2.5° × 2.5°) reanalysis data for 1981–2016. The 10-day air parcel backward trajectories were produced for the extended wet season (October–April) as well as the early and late summer. Analysis of a 36-year

The Madden Julian oscillation (MJO) has a systematic influence on the state of the extratropical atmosphere. The physical mechanism involves teleconnections from tropical deep convective heat sources through wave propagation. MJO heating resembles a propagating dipole that cycles through phases on a timescale similar to the response timescale. This complicates the attribution of the response to a well

The impact of climate change on Sahel precipitation suffers from large uncertainties and is strongly model-dependent. In this study, we analyse sources of inter-model spread in Sahel precipitation change by decomposing precipitation into its dynamic and thermodynamic terms, using a large set of climate model simulations. Results highlight that model uncertainty is mostly related to the response of

The Caribbean seasonal rainfall cycle and its characteristics are heavily relied upon by the region’s inhabitants for their socioeconomic needs; the prediction of its variability would be valuable to society. An important way to understand the predictability of the Caribbean rainfall cycle is to study its interannual variability. Previous studies vary as to how and what large-scale climate driver(s)

A systematic analysis of the main weather types influencing southern Australian rainfall is presented for the period 1979–2015. This incorporates two multi-method datasets of cold fronts and low pressure systems, which indicate the more robust fronts and lows as distinguished from the weaker and less impactful events that are often indicated only by a single method. The front and low pressure system

An interdecadal change of the North Pacific teleconnection pattern in the upper troposphere in boreal spring was noted around the late 1990s. During the period of 1979–1998, a meridional dipole pattern with alternative cyclone and anticyclone to the south and the north of 45° N over North Pacific, was identified as the leading mode by applying the empirical orthogonal function (EOF) technique onto

Brazil experiences extreme weather and climate events that cause numerous economic and social losses, and according to climate change projections, these events will increase in intensity and frequency over this century.This study adds to the body of research on Brazil’s climate change by analyzing the historical patterns and projected changes in temperature and precipitation extremes across Brazil

Differing from the Indian Ocean dipole (IOD) that has sea surface temperature anomalies (SSTAs) of opposing signs over the tropical southeastern and western Indian Ocean, a tripole pattern, characterized by positive (negative) SSTAs over the tropical central (southeastern and western) Indian Ocean, is observed and named the Indian Ocean tripole (IOT). This study proposes the concept of the IOT and

This study reveals a significant in-phase relationship between the South China Sea summer monsoon (SCSSM) withdrawal date and tropical cyclone (TC) genesis over the western North Pacific (WNP). The number of TCs generated over the WNP from mid-September to mid-October is positively correlated with the SCSSM withdrawal date during the period of 1979–2016. The decreased (increased) number of TCs generated

Seasonal forecasts of variables like near-surface temperature or precipitation are becoming increasingly important for a wide range of stakeholders. Due to the many possibilities of recalibrating, combining, and verifying ensemble forecasts, there are ambiguities of which methods are most suitable. To address this we compare approaches how to process and verify multi-model seasonal forecasts based

The original article can be found online.

Tropical floodplains have a significant impact on the regional water cycle and on land-atmosphere interaction but are not always considered in Land Surface Models (LSMs) or in Earth system models. This study evaluates the importance of representing tropical floodplains in an LSM to provide realistic river discharges, evapotranspiration fluxes and other variables crucial for land’s interaction with

The Atlantic meridional overturning circulation (AMOC) is one of the main drivers of climate variability at decadal and longer time scales. As there are no direct multi-decadal observations of this key circulation, the reconstruction of past AMOC variations is essential. This work presents a step forward in reconstructing the AMOC using climate models and time-varying surface nudging of salinity and

The Holocene moisture–temperature correlation on varying spatial–temporal scales in arid Central Asia (ACA) is still controversial. It has been widely reported that ACA experienced multi-centennial alternations between warm/dry and cold/wet climates over the past two millennia. However, less attention has focused on orbital-scale moisture–temperature relationship at a regional scale across ACA. Here

The boreal-winter stratospheric sudden warming (SSW) events and their prediction skills by an operational numerical weather prediction model are examined by applying the Global/Regional Integrated Model system (GRIMs) for 18 SSW events from 1980–2012. Based on the mean squared skill score of the 10-hPa geopotential height field, which considers the SSW spatial structure, most SSW events are predicted

Regional Climate-Weather Research and Forecasting model (CWRF) simulations driven by the ECMWF-Interim reanalysis (ERI) showed that cumulus parameterization significantly impacts daily 95th percentile precipitation (P95) over the US Gulf States (GS) and Central-Midwest States (CM). This study compared interannual variations across ERI and five CWRF cumulus parameterization members based on CM and GS

This paper examines the projected changes in rainfall in Southeast Asia (SEA) in the twenty-first century based on the multi-model simulations of the Southeast Asia Regional Climate Downscaling/Coordinated Regional Climate Downscaling Experiment–Southeast Asia (SEACLID/CORDEX–SEA). A total of 11 General Circulation Models (GCMs) have been downscaled using 7 Regional Climate Models (RCMs) to a resolution

The response of the early winter Northern Hemisphere stratospheric polar vortex and tropospheric Arctic Oscillation to anomalous autumn snow cover in Eurasia is evaluated in four operational subseasonal forecasting models. Of these four models, the two with finer stratospheric resolution simulate a weakened vortex for hindcasts initialized with more extensive snow as compared to those with less extensive

Originating in the Tianshan Mountains in arid Central Asia, the natural discharge change of the Naryn River is strongly affected by climate change. As the main source of water for the region, this river is crucial to both the natural environment and the socio-economic development. To extend the discharge record and better understand past and future changes in Naryn River discharge, we developed four

The Pacific Decadal Oscillation (PDO), the leading mode of Pacific decadal sea surface temperature variability, arises mainly from combinations of regional air-sea interaction within the North Pacific Ocean and remote forcing, such as from the tropical Pacific and the Atlantic. Because of such a combination of mechanisms, a question remains as to how much PDO variability originates from these regions

Two long continuous regional climate simulations over China have been carried out using the Regional Climate Model version 4 (RegCM4) and Weather Research and Forecasting model (WRF). The Simulations are forced by NCEP Reanalysis II data with a horizontal grid spacing of 30 km during 1981–2010. It is demonstrated that the RegCM4 and WRF had pronounced temperature and precipitation downscaling ability

This study revisits the impacts of different types of El Niño on East Asian summer precipitation (EASP) with observed and re-analyzed data from 1958 to 2015. It focuses on the boreal summer preceding peaks of El Niño when prominent SST anomalies are mainly situated in the tropical Pacific. Distinct responses of EASP are obtained for the three identified types of SST anomalies noted as summer EP (Eastern

In 2012, extreme anomalous climate conditions occurred around the globe. Large areas of North America experienced an anomalously hot summer, with large precipitation deficits inducing severe drought. Over Europe, the summer of 2012 was marked by strong precipitation anomalies with the UK experiencing its wettest summer since 1912 while Spain suffered severe drought. What caused these extreme climate

We use an unprecedented ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide, for the first time, an RCM-based global view of monsoon changes at various levels of increased greenhouse gas (GHG) forcing. All regional simulations are conducted using RegCM4 at a 25 km horizontal grid spacing using lateral and lower boundary forcing from three General Circulation

A multi-parameter, absolute-dated lacustrine record from the eastern Tibetan Plateau provides a continuous history of the Asian summer monsoon (ASM) over the past ~ 6000 years. The record broadly follows the trend in northern hemisphere summer insolation. However, it diverges during a period of increased moisture and thermal conditions during the past ~ 1300 years, broadly corresponding to the ASM

Global temperature increases are most clearly detected in the shifting distribution of extreme events. Australia’s warming climate has resulted in significant changes in the frequency of temperature extremes, with a general increase in heatwaves and a reduction in the number of cold days. Here, we present the longest historical analysis of daily Australian temperature extremes and their societal impacts