Developed regions of the world represent a major atmospheric methane (CH4) source, but these regional emissions remain poorly constrained. The Yangtze River Delta (YRD) region of China is densely populated (about 16% of China’s total population) and consists of large anthropogenic and natural CH4 sources. Here, atmospheric CH4 concentrations measured at a 70-m tall tower in the YRD are combined with

Long-term, ground-based daily global solar radiation (DGSR) at Zhongshan Station in Antarctica can quantitatively reveal the basic characteristics of Earth’s surface radiation balance and validate satellite data for the Antarctic region. The fixed station was established in 1989, and conventional radiation observations started much later in 2008. In this study, a random forest (RF) model for estimating

A positivity-preserving conservative semi-Lagrangian transport model by multi-moment finite volume method has been developed on the cubed-sphere grid. Two kinds of moments (i.e., point values (PV moment) at cell interfaces and volume integrated average (VIA moment) value) are defined within a single cell. The PV moment is updated by a conventional semi-Lagrangian method, while the VIA moment is cast

Gross primary production (GPP) plays a crucial part in the carbon cycle of terrestrial ecosystems. A set of validated monthly GPP data from 1957 to 2010 in 0.5° × 0.5° grids of China was weighted from the Multi-scale Terrestrial Model Intercomparison Project using Bayesian model averaging (BMA). The spatial anomalies of detrended BMA GPP during the growing seasons of typical El Niño years indicated

Space-borne measurements of atmospheric greenhouse gas concentrations provide global observation constraints for top-down estimates of surface carbon flux. Here, the first estimates of the global distribution of carbon surface fluxes inferred from dry-air CO2 column (XCO2) measurements by the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite (TanSat) are presented. An ensemble

The deep ocean below 2000 m is a large water body with the sparsest data coverage, challenging the closure of the sea-level budget and the estimation of the Earth’s energy imbalance. Whether the deep ocean below 2000 m is warming globally has been debated in the recent decade. However, as the regional signals are generally larger than the global average, it is intriguing to investigate the regional

Under external heating forcing in the Southern Ocean, climate models project anomalous northward atmosphere heat transport (AHT) across the equator, accompanied by a southward shift of the intertropical convergence zone (ITCZ). Comparison between a fully coupled and a slab ocean model shows that the inclusion of active ocean dynamics tends to partition the cross-equatorial energy transport and significantly

All-sky (i.e., clear, cloudy, and precipitating conditions) assimilation of microwave observations shows potentially positive impacts on the improvement of the forecasts of cloud-associated weather processes. In this study, a typical mei-yu heavy precipitation event that occurred in 2017 was investigated, and the Weather Research and Forecasting data assimilation (WRFDA) as well as its 3D-Var assimilation

Correcting the forecast bias of numerical weather prediction models is important for severe weather warnings. The refined grid forecast requires direct correction on gridded forecast products, as opposed to correcting forecast data only at individual weather stations. In this study, a deep learning method called CU-net is proposed to correct the gridded forecasts of four weather variables from the

The quality of ensemble forecasting is seriously affected by sample quality. In this study, the distributions of ensemble members based on the observed track and intensity of tropical cyclones (TCs) were optimized and their influence on the simulation results was analyzed. Simulated and observed tracks and intensities of TCs were compared and these two indicators were combined and weighted to score

Record ozone loss was observed in the Arctic stratosphere in spring 2020. This study aims to determine what caused the extreme Arctic ozone loss. Observations and simulation results are examined in order to show that the extreme Arctic ozone loss was likely caused by record-high sea surface temperatures (SSTs) in the North Pacific. It is found that the record Arctic ozone loss was associated with the

The autumn Intertropical Convergence Zone (ITCZ) over the South China Sea (SCS) is typically held south of 10°N by prevailing northeasterly and weakening southwesterly winds. However, the ITCZ can move north, resulting in heavy rainfall in the northern SCS (NSCS). We investigate the mechanisms that drove the northward movement of the ITCZ and led to heavy non-tropical-cyclone rainfall over the NSCS

Melt ponds significantly affect Arctic sea ice thermodynamic processes. The melt pond parameterization scheme in the Los Alamos sea ice model (CICE6.0) can predict the volume, area fraction (the ratio between melt pond area to sea ice area in a model grid), and depth of melt ponds. However, this scheme has some uncertain parameters that affect melt pond simulations. These parameters could be determined

The satellite-based quantification of cloud radiative forcing remains poorly understood, due largely to the limitation or uncertainties in characterizing cloud-base height (CBH). Here, we use the CBH data from radiosonde measurements over China in combination with the collocated cloud-top height (CTH) and cloud properties from MODIS/Aqua to quantify the impact of CBH on shortwave cloud radiative forcing

Initial errors in the tropical Indian Ocean (IO-related initial errors) that are most likely to yield the Spring Prediction Barrier (SPB) for La Niña forecasts are explored by using the CESM model. These initial errors can be classified into two types. Type-1 initial error consists of positive sea temperature errors in the western Indian Ocean and negative sea temperature errors in the eastern Indian

Initial condition and model errors both contribute to the loss of atmospheric predictability. However, it remains debatable which type of error has the larger impact on the prediction lead time of specific states. In this study, we perform a theoretical study to investigate the relative effects of initial condition and model errors on local prediction lead time of given states in the Lorenz model.

Record-breaking heavy and persistent precipitation occurred over the Yangtze River Valley (YRV) in June–July (JJ) 2020. An observational data analysis has indicated that the strong and persistent rainfall arose from the confluence of southerly wind anomalies to the south associated with an extremely strong anomalous anticyclone over the western North Pacific (WNPAC) and northeasterly anomalies to the

Cloud Masking is one of the most essential products for satellite remote sensing and downstream applications. This study develops machine learning-based (ML-based) cloud detection algorithms using spectral observations for the Advanced Himawari Imager (AHI) onboard the Himawari-8 geostationary satellite. Collocated active observations from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) are

In the summer of 1998, heavy rainfall persisted throughout the summer and resulted in a severe prolonged flooding event over East Asia. Will a similar rainy summer happen again? To date, many studies have investigated projected changes in the seasonality or daily extreme precipitation events over East Asia; however, few studies have focused on the changes in extreme summer-averaged East Asian rainfall

During June and July of 2020, the Yangtze River basin suffered from extreme mei-yu rainfall and catastrophic flooding. This study explores the seasonal predictability and associated dynamical causes for this extreme Yangtze River rainfall event, based on forecasts from the Met Office GloSea5 operational forecast system. The forecasts successfully predicted above-average rainfall over the Yangtze River

Characterized by scarce water resources and fragile ecosystems, Northwest China (NWC) has experienced a climate shift from warm-dry to warm-wet conditions since the 1980s that has garnered extensive concern in recent years. In this study, the variability in extreme precipitation (EP) during 1961–2016 in different climate zones of NWC and the possible mechanisms for this variation are investigated.

In August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled ice-ocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978 (mean value of 1

The existence of outliers can seriously influence the analysis of variational data assimilation. Quality control allows us to effectively eliminate or absorb these outliers to produce better analysis fields. In particular, variational quality control (VarQC) can process gray zone outliers and is thus broadly used in variational data assimilation systems. In this study, governing equations are derived

This article introduces “EarthLab”, a major new Earth system numerical simulation facility developed in China. EarthLab is a numerical simulation system for a physical climate system, an environmental system, an ecological system, a solid earth system, and a space weather system as a whole with a high-performance scientific computing platform. EarthLab consists of five key elements—namely: a global

MetCoOp is a Nordic collaboration on operational Numerical Weather Prediction based on a common limited-area km-scale ensemble system. The initial states are produced using a 3-dimensional variational data assimilation scheme utilizing a large amount of observations from conventional in-situ measurements, weather radars, global navigation satellite system, advanced scatterometer data and satellite

As Volatile Organic Compounds (VOCs) are one of the precursors of ozone, their distribution and variable concentrations are highly related to local ozone pollution control. In this study, we obtained vertical profiles of VOCs in Shanghai’s Jinshan district on 8 September and 9 September in 2016 to investigate their distribution and impact on local atmospheric oxidation in the near surface layer. Vertical

Multiaxis differential absorption spectroscopy (MAX-DOAS) is a newly developed advanced vertical profile detection method, but the vertical nitrogen dioxide (NO2) profiles measured by MAX-DOAS have not yet been fully verified. In this study, we perform MAX-DOAS and tower gradient observations to simultaneously acquire tropospheric NO2 observations in the Beijing urban area from 1 April to 31 May 2019

Iron and oxalic acids are widely distributed in the atmosphere and easily form ferric oxalate complex (Fe(III)-Ox). The tropospheric aqueous-phase could provide a medium to enable the photo-Fenton reaction with Fe(III)-Ox under solar irradiation. Although the photolysis mechanisms of Fe(III)-Ox have been investigated extensively, information about the oxidation of volatile organic compounds (VOC),

Black carbon (BC) reduces the photolysis coefficient by absorbing solar radiation, thereby affecting the concentration of ozone (O3) near the ground. The influence of BC on O3 has thus received much attention. In this study, Mie scattering and the tropospheric Ultraviolet and Visible radiation model are used to analyze the effect of BC optical properties on radiation. Combined with data of O3 precursors

Acetaldehyde is one of the important VOC species of O3 precursors in the atmospheric environment. The influences of relative humidity (RH) and initial VOC/NOx ratio (RCN) on the formation of O3 are studied in smog chamber experiments, and the MCM v3.3.1 mechanism of acetaldehyde is modified based on the experimental results. In low-RH conditions (RH = 11.6%±1.1%), the O3 concentration at 6 h increases

The improvement of the accuracy of simulated cloud-related variables, such as the cloud fraction, in global climate models (GCMs) is still a challenging problem in climate modeling. In this study, the influence of cloud microphysics schemes (one-moment versus two-moment schemes) and cloud overlap methods (observation-based versus a fixed vertical decorrelation length) on the simulated cloud fraction

In summer 2020, extreme rainfall occurred throughout the Yangtze River basin, Huaihe River basin, and southern Yellow River basin, which are defined here as the central China (CC) region. However, only a weak central Pacific (CP) El Niño happened during winter 2019/20, so the correlations between the El Niño-Southern Oscillation (ENSO) indices and ENSO-induced circulation anomalies were insufficient

Accurate prediction of tropical cyclone (TC) intensity remains a challenge due to the complex physical processes involved in TC intensity changes. A seven-day TC intensity prediction scheme based on the logistic growth equation (LGE) for the western North Pacific (WNP) has been developed using the observed and reanalysis data. In the LGE, TC intensity change is determined by a growth term and a decay

The partial cycle (PC) strategy has been used in many rapid refresh cycle systems (RRC) for regional short-range weather forecasting. Since the strategy periodically reinitializes the regional model (RM) from the global model (GM) forecasts to correct the large-scale drift, it has replaced the traditional full cycle (FC) strategy in many RRC systems. However, the extra spin-up in the PC strategy increases

High spectral resolution (or hyperspectral) infrared (IR) sounders onboard low earth orbiting satellites provide high vertical resolution atmospheric information for numerical weather prediction (NWP) models. In contrast, imagers on geostationary (GEO) satellites provide high temporal and spatial resolution which are important for monitoring the moisture associated with severe weather systems, such

Future changes in tropical cyclone (TC) activity over the western North Pacific (WNP) under the representative concentration pathway RCP4.5 are investigated based on a set of 21st century climate change simulations over East Asia with the regional climate model RegCM4 driven by five global models. The RegCM4 reproduces the major features of the observed TC activity over the region in the present-day

The tropical storm day (TSD) is a combined measure of genesis and lifespan. It reflects tropical cyclone (TC) overall activity, yet its variability has rarely been studied, especially globally. Here we show that the global total TSDs exhibit pronounced interannual (3–6 years) and decadal (10 years) variations over the past five-to-six decades without a significant trend. The leading modes of the interannual

Freshwater is recharged mainly by rainfall and stored inland for a period of time, which is directly affected by its storage capability. The storage capability of river basins has different spatiotemporal features that are important for the predictability of freshwater resources. However, the estimation of freshwater storage capability (FSC) remains a challenge due to the lack of observations and quantification

Three extreme cold events invaded China during the early winter period between December 2020 to mid-January 2021 and caused drastic temperature drops, setting new low-temperature records at many stations during 6–8 January 2021. These cold events occurred under background conditions of low Arctic sea ice extent and a La Niña event. This is somewhat expected since the coupled effect of large Arctic

This study uses the WRF-Chem model combined with the empirical kinetic modeling method (EKMA curve) to study the compound pollution event in Beijing that happened in 13–23 May 2017. Sensitivity tests are conducted to analyze ozone sensitivity to its precursors, and to develop emission reduction measures. The results suggest that the model can accurately simulate the compound pollution process of photochemistry

In the study of diagnosing climate simulations and understanding the dynamics of precipitation extremes, it is an essential step to adopt a simple model to relate water vapor condensation and precipitation, which occur at cloud-microphysical and convective scales, to large-scale variables. Several simple models have been proposed; however, improvement is still needed in both their accuracy and/or the

Weather manifests in spatiotemporally coherent structures. Weather forecasts hence are affected by both positional and structural or amplitude errors. This has been long recognized by practicing forecasters (cf., e.g., Tropical Cyclone track and intensity errors). Despite the emergence in recent decades of various objective methods for the diagnosis of positional forecast errors, most routine verification

The development and evolution of precipitation microphysical parameters and the vertical structure characteristics associated with Typhoon Yagi (201814) are analyzed in the city of Jinan, Shandong Province based primarily on the observations of a micro rain radar (MRR), a cloud radar, and a disdrometer. The precipitation process is further subdivided into four types: convective, stratiform, mixed,

Convective/large-scale (C/L) precipitation partitions are crucial for achieving realistic rainfall modeling and are classified in 16 phase 6 of the Coupled Model Intercomparison Project (CMIP6) atmospheric models. Only 4 models capture the feature that convective rainfall significantly exceeds the large-scale rainfall component in the tropics while the other 12 models show 50%–100% large-scale rainfall

The presence of embedded convection in stratiform clouds strongly affects ice microphysical properties and precipitation formation. In situ aircraft measurements, including upward and downward spirals and horizontal penetrations, were performed within both embedded convective cells and stratiform regions of a mixed-phase stratiform cloud system on 22 May 2017. Supercooled liquid water measurements

Large-ensemble simulations of the atmosphere-only time-slice experiments for the Polar Amplification Model Intercomparison Project (PAMIP) were carried out by the model group of the Chinese Academy of Sciences (CAS) Flexible Global Ocean-Atmosphere-Land System (FGOALS-f3-L). Eight groups of experiments forced by different combinations of the sea surface temperature (SST) and sea ice concentration (SIC)

This study explores the structures of the correlations between infrared (IR) brightness temperatures (BTs) from the three water vapor channels of the Advanced Baseline Imager (ABI) onboard the GOES-16 satellite and the atmospheric state. Ensemble-based data assimilation techniques such as the ensemble Kalman filter (EnKF) rely on correlations to propagate innovations of BTs to increments of model state

As the key precursors of O3, anthropogenic non-methane volatile organic compounds (NMVOCs) have been studied intensively. This paper performed a meta-analysis on the spatial and temporal variations of NMVOCs, their roles in photochemical reactions, and their sources in China, based on published research. The results showed that both non-methane hydrocarbons (NMHCs) and oxygenated VOCs (OVOCs) in China

Independent datasets consistently indicate a significant correlation between the sea ice variability in the Bering Sea during melt season and the summer rainfall variability in the Lake Baikal area and Northeastern China. In this study, four sea ice datasets (HadISST1, HadISST2.2, ERA-Interim and NOAA/NSIDC) and two global precipitation datasets (CRU V4.01 and GPCP V2.3) are used to investigate co-variations

This study investigates the circulation and precipitation anomalies associated with different configurations of the western North Pacific subtropical high (WNPSH) and the East Asian westerly jet (EAJ) in summer on interannual timescales. The in-phase configuration of the WNPSH and EAJ is characterized by the westward (eastward) extension of the WNPSH and the southward (northward) shift of the EAJ,

Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure

We use FLIGHT+ aircraft reconnaissance data for tropical cyclones (TCs) in the North Atlantic and Eastern Pacific from 1997 to 2015 to re-examine TC fullness (TCF) characteristics at the flight level. The results show a strong positive correlation between the flight-level TCF and the intensity of TCs, with the flight-level TCF increasing much more rapidly than the near-surface TCF with increasing intensity

Photochemical smog characterized by high concentrations of ozone (O3) is a serious air pollution issue in the North China Plain (NCP) region, especially in summer and autumn. For this study, measurements of O3, nitrogen oxides (NOx), volatile organic compounds (VOCs), carbon monoxide (CO), nitrous acid (HONO), and a number of key physical parameters were taken at a suburban site, Xianghe, in the NCP

China experienced significant flooding in the summer of 2020 and multiple extreme cold surges during the winter of 2020/21. Additionally, the 2020 typhoon season had below average activity with especially quiet activity during the first half of the season in the western North Pacific (WNP). Sea surface temperature changes in the Pacific, Indian, and Atlantic Oceans all contributed to the heavy rainfall

Ozone vertical column densities (VCDs) were retrieved by Zenith Scattered Light-Differential Optical Absorption Spectroscopy (ZSL-DOAS) from January 2017 to February 2020 over Fildes Peninsula, West Antarctica (62.22°S, 58.96°W). Each year, ozone VCDs started to decline around July with a comparable gradient around 1.4 Dobson Units (DU) per day, then dropped to their lowest levels in September and

The accuracy of passive satellite cloud top height (CTH) retrieval shows regional dependence. This paper assesses the CTH derived from the FY-4A and Himawari-8 satellites through comparison with those from the ground-based millimeter radar at two sites: Yangbajing, Tibet, China (YBJ), and the Institute of Atmospheric Physics (IAP), Beijing, China. The comparison shows that Himawari-8 missed more CTHs

Amines are important for new particle formation and subsequent growth in the atmosphere. Consequently, the processes involved are receiving more attention in recent years. Here, we conduct a field observation in order to investigate the atmospheric particulate amines at a background site in the Yangtze River Delta (YRD) during the summer of 2018. Four amines in PM2.5, i.e., methylamine (MA), dimethylamine

In this study, the ability of the Weather Research and Forecasting (WRF) model to generate accurate near-surface wind speed forecasts at kilometer- to subkilometer-scale resolution along race tracks (RTs) in Chongli during the wintertime is evaluated. The performance of two postprocessing methods, including the decaying-averaging (DA) and analogy-based (AN) methods, is tested to calibrate the near-surface

Short-duration snow bursts with heavy snow represent one type of hazardous weather in winter which can be easily missed by the winter weather warnings but often results in great hazards. In this paper, the mechanism for the occurrence of such events was investigated with the aid of a localized terrain-influenced snow burst event in Northeast China. The snow burst was produced by an eastward-moving

In recent years, several studies pointed out that anthropogenic emission sources in China which significantly contribute to the PM2.5 mass burden was an important cause of particulate pollution in South Korea. However, most studies generally focused upon a single pollution event. It is rare to see comprehensive research that captures those features prone to interannual variations concerning the transboundary