The cause for zonal oscillation of the western Pacific subtropical high (WPSH) on a quasi-biweekly (10–20-day) timescale was investigated. Both relative vorticity and geopotential height anomalies exhibit a maximum activity center over the western edge of the climatological WPSH. The quasi-biweekly WPSH oscillation is closely related to a northwestward-propagating quasi-biweekly oscillation (QBWO)

The integrals of lightning current and its square over time, named as the electrical charge quantity and lightning current action integral, respectively, are indicative of the total charges and heat energy released by the lightning. The temperature of air molecules along the discharging path is thus increased and can be observed by a properly-configured ground-based microwave radiometer which is originally

Currently, high-resolution severe storm observations obtained by vehicle-mounted mobile X-band dual-polarization radar (X-pol) are widely used in severe storm structure and dynamics studies; however, the identification of hailstones based on X-pol is still rare, leading to the limited application of X-pol in identifying hydrometeors in the microphysical processes of severe storms. Based on previous

In this study, we examine the seasonal variability and long–term trends in aerosol distribution over peninsular Southeast Asia (SEA: 90°–105°E, 15°–28°N) based on MERRA–2 reanalysis datasets for a period of 30 years (1985–2015). Special emphasis has been given on the loading and distribution of carbonaceous aerosols, in response to changes in vegetation cover and biomass burning over SEA. MERRA–2 reanalysis

An adaptive localization method using the hierarchical ensemble filter (HEF) technique was first applied to the ensemble Kalman filter (EnKF) radar data assimilation (DA) though observing system simulation experiments (OSSEs) for an idealized supercell storm. The HEF method calculates localization by minimizing the sampling error without defining the physical distance between observation and state

The selection of global climate models (GCMs) for a region remained a difficult step in climate change studies. A state-of-the-art Support Vector Machine Recursive Feature Elimination (SVM-RFE) algorithm is proposed in this paper for GCM selection. The ranking of GCMs obtained using SVM-RFE was compared to that obtained using entropy-based similarity assessment index known as Symmetrical Uncertainty

A study of ions sources and water vapor sources was carried out from April 1, 2016 to October 31, 2018, at Zhimenda(ZMD), Qumalai(QML) and Tuotuohe(TTH) in the source region of the Yangtze River to obtain preliminary quantitative results for the contributions of the ion and water vapor sources. In the study, 489 precipitation samples analyzed for pH, EC, and ionic concentrations were evaluated by using

The MODerate resolution Imaging Spectroradiometer (MODIS) is one of the most widely used meteorological remote sensing instruments. Its Dark Target aerosol optical depth (AOD) product has been widely used in environment and meteorology researches, such as model evaluation and data assimilation. However, this product has a low coverage under conditions of heavy haze in China. This is because the haze

Tibetan Plateau vortices (TPVs), generated over the Tibetan Plateau, are important rainfall triggers in southwestern and eastern China when moving off the plateau. The heavy rainfall event that occurred over southwestern China in early July 2018 caused severe floods and landslides, leading to substantial damage to normal production and life. In this work, the roles of TPVs in the rainfall are investigated

During the Chinese National Arctic Research Expedition in 2018 (CHINARE 2018), 84 radiosondes were released over the Pacific sector of the Arctic Ocean. Using these data, the characteristics of the atmospheric vertical structure with different sea ice covers were studied. The results showed that (1) typical temperature inversions were found in the low-level atmosphere with various characteristics over

Based on the three-dimensional moist potential vorticity (MPV) equation and diabatic heating excluding latent heating (Q*), a Lagrangian vertical vorticity equation is deduced for a saturated atmosphere. The convective stability and water vapor are considered in this equation, and the impacts of sensible heating and radiative heating on the vertical vorticity development are focused. This MPV-Q* theory

Few related studies have been carried out for northwest China's the inland, although the increasing inorganic reactive nitrogen (Nr) deposition and severe air pollution in China have attracted considerable attention. Based on eight-year measurements of the concentrations of NH3, HNO3, particulate (p) NH4+, pNO3−, and NO2 in the air and inorganic nitrogen (NH4+, NO3−) in the precipitation at a rural

This study aims to identify the main causes of extreme rainfall events specifically recent ones that occurred in Central East Africa, which seriously affected the western part of Burundi causing 77 deaths, destruction of infrastructures, loss of properties and hectares of lands in February, 2014. To understand underlying issues about extreme rainfall occurrence and its key drivers, the present study

Past Results indicate that there is a significant negative correlation between the Siberian High (SH) and winter surface air temperature (SAT) over Eurasian continent and East Asia. However, correlation does not mean causation, especially in nonlinear dynamic systems. Here, we apply a recently developed method, Convergent Cross Mapping (CCM), to detect the causal connection between SH and winter SAT

A gridded precipitation dataset derived from the high-density rain gauge network of the Ebro River Basin Authority is used to evaluate the performance of Integrated Multi-satellitE Retrievals for GPM (IMERG) level-3 estimates. Although aggregated values compare well, several differences are found between climate regions. The research investigates the role of orography and gauge density on IMERG performance

The Ru River Basin is facing severe water security challenges such as frequent occurrence of extreme events and serious nutrient enrichment of its water bodies. In simulating daily streamflow, monthly total nitrogen (TN) loads, and monthly total phosphorous (TP) loads of the basin, the SWAT (Soil and Water Assessment Tool) model utilizing hourly rainfall inputs was found to perform considerably better

With the continuous deepening of hydrological simulations in the alpine regions, high-resolution rainfall data is urgently needed as driving data for distributed hydrological models. Therefore, the objective of this study is to evaluate the performance of the WRF model for the accumulated rainfall simulations in the central segment of the Tianshan Mountains. The WRF model is configured with triple

This study investigated the sensitivity of the western North Pacific (WNP) summer precipitation to the convection schemes and discussed the associated dynamical processes. Two convection schemes were compared: one is the default mass-flux convection scheme used in the state-of-the-art ECHAM6.3 atmosphere model and the other incorporates the Stochastic Multicloud Model (SMCM) into ECHAM6.3. Incorporation

Based on the daily maximum temperature data from Chinese metrological stations, the frequency of extreme hot event (EHE) in Northeast China (NEC) over the period from 1960 to 2018 is investigated. The results show that the EHE frequency in summer (June and July) experienced a significant interdecadal increase around the mid-1990s. The analysis of the possible mechanism indicates that the interdecadal

The altitude rocket-and-wire technique was used to trigger lightning to strike a 30-m-high communication tower. A comprehensive dataset was obtained, including discharge current and electromagnetic-field changes, as well as high-speed video images. An attachment process with an abnormal circuitous S-shaped connection channel was observed between the lower extremity of the triggering wire and the tower

Climate change effects can have significant impacts worldwide. Extreme events can modify water availability and agricultural production, making climate change planning an essential task. The National Institute for Space Research (INPE in Portuguese) in Brazil has made a large dataset of regional climate model outputs (simulations and projections) available, which opens up many possibilities of carrying

Heat waves in China were projected under 1.5 °C and 2 °C of warming targets using the bias-adjusted simulations of 4 GCMs obtained from ISIMIP2b. The simulations of GCMs on heat wave over China during historical period of 1986–2005 were examined against daily gridded observation CN05 from National Meteorological Information Center of China. In this evaluation, three heat wave definitions respectively

Tipping-bucket rain gauges (TBRGs) are an established and proven means of recording rainfall amount, but are not well-suited to the estimation of rainfall duration, owing to lag times arising from bucket filling. TBRG data are unable to reveal aspects of rainfall arrival such as short-term rainfall intermittency; nor can they adequately capture the start and end times of low intensity rain. These limitations

The variations of atmospheric compositions (ACs) can change the atmospheric interactions with other parts of the ecosystem, and it also affects the energy budget of the Earth. Satellite remote sensing plays a crucial role in monitoring AC by providing a matchless global perspective with consistency over long periods. Although China started space exploration missions in the early 1970s, the situation

Although variations of atmospheric dust aerosols emitted from different sources within Asia have been studied separately in previous research, the characteristics and causes of these changes have not been fully explored. This study used the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) data set for 1980–2016 to compare seasonal and interannual variations of atmospheric

The breeze phenomenon is of great importance in coasts around the world owing to both its impact on local atmospheric dynamics and its influence on coastal processes. The northwest of the Yucatan Peninsula (YP) is characterized by the presence of intense sea breezes and Cold Surge (CS) events (locally known as Nortes). Field observations suggest that nearshore hydrodynamics and beach evolution in the

In this study, the spatiotemporal distribution of the NO2 and SO2 Vertical Columns Densities (VCDs) in the North China Plain (NCP) region was measured by long-distance mobile measurements using a mobile Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument. The mobile observations were performed in both summer (July 2017) and winter (January and February 2018) and the total

The airborne particulate matter (PM) is known to cause adverse pulmonary and cardiovascular health effects. This study investigated the diurnal characteristics of PM induced PM-bound ROS from real time measurements in typical roadside and urban background sites in Hong Kong, and identified potential influencing factors to its variation in atmosphere. A nitroxide probe (BPEAnit) was employed in the

In this study, PM10 aerosol samples were collected at 4 urban and 1 rural sites in the region of Cienfuegos (Cuba) and analyzed for their chemical compositions (total carbon (TC), total nitrogen (TN), NH4+, Cl−, NO3− and SO42−) and their stable carbon (δ13C) and nitrogen (δ15N), and radioactive (210Pb, 7Be, 137Cs and 40K) isotope systematics, in order to better constrain both their sources of pollution

Satellite precipitation product estimates (SPPEs) provide rainfall data on regional and global scales and have the potential to be applied in various fields. Several satellite precipitation estimates are available for their various features in retrieval algorithms, used sensor instrument, spatial–temporal resolution, and coverage area. Global Satellite Mapping of Precipitation (GSMaP), Integrated MultisatellitE

This paper reports the first investigations of the mid-latitude convective boundary layer (CBL) electricity above the homogeneous land surface using a large-eddy simulation (LES). Our approach uses LES together with a subgrid kinematic model for relative dispersion of scalar to calculate Lagrangian trajectories of notional particles carrying radioactive nuclei, small atmospheric ions, and charged aerosol

In recent decades, the northern hemisphere (NH) atmospheric meridional circulation has experienced unprecedented changes. The NH tropical belt is significantly expanding toward high latitudes, and the Arctic polar vortex is continually weakening. Both phenomena have led to severe consequences on the Earth's surface, such as more frequent droughts in the subtropics and accelerated sea ice loss in the

Laboratory generated aerosols and aerosol sampled in a field campaign were studied to assess the repeatability of heterogeneous ice activation processes and verify if the ice nuclei particles maintained their nucleating capability. Experiments were performed using a filter technique, i.e. aerosol particles were sampled on black-gridded cellulose nitrate membrane filters and assessed for ice nucleating

Dust storm originates from arid and semiarid areas and could cause worldwide lasting effects along varying trajectories. As an extreme weather hazard, dust storm is usually induced by strong winds. In this paper, an aerodynamic parameter, defined as the ratio between dust storm frequency (DSF) and strong wind frequency (SWF), was calculated for quantifying dust storm susceptibility (DSS). The characteristic

Three years of measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on Aqua satellite has been used to develop a new approach to quantify the well-known, yet unresolved zonal bias in MODIS LWP of marine clouds. This new method utilizes two parameters: the solar zenith angle and cloud heterogeneity index, both of which are available for each MODIS pixel. Comparisons

A new methodology based on optical parameters from integrating nephelometer measurements and chemically speciated PM10 mass concentrations, to associate intensive optical parameters with pollution sources identified by the Positive Matrix Factorization (PMF) technique, is presented. PM10 samplings and integrating nephelometer measurements at 450, 525, and 635 nm, co-located in space and time, were

Understanding long-term drought variations in the past can help us to evaluate ongoing and future hydroclimate changes in the arid western Chinese Loess Plateau. The present study generated a new stable oxygen isotope (δ18O) chronology composed of five individual Pinus tabulaeformis Carr. isotope series from Mt. Shimen, China. Correlation function analysis revealed that the composite tree-ring δ18O

The Beijing-Tianjin-Hebei (BTH) region is the largest industrial cluster in northern China and its most prominent air pollution zone. Industrial emissions of PM2.5, SO2, NOx and other pollutants have a significant impact on regional air quality. Monitoring industrial pollution emissions is of great significance for the prevention and control of air pollution. The VIIRS Nightfire products can detect

We use machine learning to generate binary forecasts of the occurrence of lightning within a particular location and time interval. The training data is weather variables found in the forecasts from the European Centre for Medium-range Weather Forecasts, correlated against subsequent lightning reports, for a region containing the Korean Peninsula. Lightning is uncommon, so the amount of data which

Radar reflectivity contains information about hydrometeors and plays an important role in the initialization of convective-scale numerical weather prediction (NWP). In this study, a new background-dependent hydrometeor retrieval method is proposed and retrieved hydrometeors are assimilated into the Weather Research and Forecasting model (WRF), with the aim of improving short-term severe weather forecasts

This study investigates the local land-atmosphere coupling (LoCo) in the rainy season by applying a mixing diagram method to the field measurements and ERA5 data over a typical underlying surface in Tibetan Plateau (TP). Comparison of frequencies of meteorological variables in June, July, August, and September (JJAS) in 2011 in the two datasets suggests that the ranges of meteorological variables are

Based on the relationship between lightning and thunderstorm microphysics, this paper aims to determine the averaged vertical profiles of polarimetric variables for different classes of lightning density according to the GLM grid and then evaluate the potential use of these profiles for data assimilation in models with high spatial and temporal resolutions. Polarimetric variables from an X-band radar

Lightning Location Systems provide detailed data on the lightning occurring within the area of the system's coverage. This kind of remote sensing equipment uses geolocation techniques to retrieve lightning cloud-to-ground return strokes. Prior to getting information regarding the number of lightning flashes, cloud-to-ground strokes need to be grouped into lightning flashes. The stroke-to-flash conversion

This study diagnoses the cause of the upper-level warm temperature anomaly (UWTA) associated with March–May (MAM) heavy rainfall of 1980–2010 in Tanzania in terms of the empirical orthogonal function (EOF), singular value decomposition (SVD) and dynamical diagnosis. EOF reveals the dominance of enhanced UWTA over the entire study region with strong warming to the northern coast, central, south-western

In recent years, persistent heavy PM2.5 pollution (PHP) events occurred frequently over the Beijing-Tianjin-Hebei (BTH) region in China, which posed a great threat to human life. This study investigates the evolution of PHP over the BTH region in China and its relation with atmospheric quasi-biweekly oscillation. A significant periodicity of 10–16 days of the PM2.5 concentration over the BTH region

Despite high impacts of recurrent droughts, studies related to drought characterization and risk assessment is very limited in Iraq due to unavailability of sufficient and reliable climate data. This paper attempts to assess the possibility of using Remotely Sensed Precipitation Data (RSPD) for monitoring droughts in Iraq. Two monthly RSPD namely, TRMM for the period 1998–2017 and PERSIANN for the

The analysis of a severe convective storm occurred in northwestern Italy during late summer 2012 is presented here. The event was characterized by heavy precipitation, hail and intense wind gusts, causing injuries and damages to trees, buildings and infrastructures. The description of the case study draws upon a wide palette of observational data. Surface and upper-air observations helped characterize

The present study investigates the effect of topography on the rainfall pattern of the North West Himalayan (NWH) region. The Weather Research and Forecasting (WRF) model is employed for conducting four dedicated experiments with varying topography at regional scale, which are assessed with respect to the control experiment of no-change in topography. Categorical validation analysis carried out for

Artificially triggered lightning is useful in scientific studies of the physical processes of lightning because it is predictable in both time and space. However, the triggering operations need to be carried out under suitable weather conditions. Ground-based microwave radiometers can be used to obtain thermodynamic information about the Earth's atmosphere and can show the evolution of atmospheric

Aerosol and CCN number concentrations, and aerosol size distributions in and around the Korean Peninsula were measured onboard the NASA DC-8 research aircraft during the KORUS-AQ campaign in May and June of 2016. The average and standard deviation values of total aerosol number concentrations (diameter > 10 nm, NCN10) in the boundary layer (below 1 km altitude) over Seoul, the Korean Peninsula, the