Tang-Huang Lin

National Central University | NCU · Center for Space and Remote Sensing Research

Satellite aerosol optical depth (AOD) provides an alternative way to depict the spatial distribution of near-surface PM2.5. In this study, a mathematical formulation of how PM2.5 is related to AOD is presented. When simplified to a linear equation, a functional dependence of the slope on the aerosol type, scattering enhancement factor f(RH), and bo...

Increasing the accuracy of rainfall forecasts is crucial as an effort to prevent hydrometeorological disasters. Weather changes that can occur suddenly and in a local scope make fast and precise weather forecasts increasingly difficult to inform. Additionally, the results of the numerical weather model used by the Indonesia Agency for Meteorology,...

This study applied positive matrix factorization (PMF) to identify the sources of size-resolved submicrometer (10–1000 nm) particles and quantify their contributions to impaired visibility based on the particle number size distributions (PNSDs), aerosol light extinction (bp), air pollutants (PM10, PM2.5, SO2, O3, and NO), and meteorological paramet...

This study investigated the hourly inorganic aerosol chemistry and its impact on atmospheric visibility over an urban area in Central Taiwan, by relying on measurements of aerosol light extinction, inorganic gases, and PM2.5 water-soluble ions (WSIs), and simulations from a thermodynamic equilibrium model. On average, the sulfate (SO4²⁻), nitrate (...

Since the 24-hr PM2.5 (particle aerodynamic diameter less than 2.5 μm) concentration standard was regulated in Taiwan in 2012, the PM2.5 concentration has been decreasing year by year, but the ozone (O3) concentration remains almost the same. In particular, the daily maximum 8-hr average O3 (MDA8 O3) concentration frequently exceeds the standard. T...

Adverse human health effects caused by fine particulate matter (PM2.5) were reported; however, source-specific PM2.5 and its bioreactivity need to be assessed to understand regional human impacts. The objective of this study was to investigate the contributions of PM2.5 to particle bioreactivity in Taichung City, an urban area of west-central Taiwa...

The long-term downward trend of NOX concentrations does not reflect the reduction of nitrate (NO3⁻) in Taiwan. Instead, the proportion of NO3⁻ in PM2.5 increased in recent years. To probe the increasing importance of NO3⁻ in PM2.5, this study applied the WRF/CMAQ modeling system to implement a simulation from 16 March 2017 to 30 April 2017, in whic...

The deterioration of visibility due to air pollutants and relative humidity has been a serious environmental problem in eastern Asia. In most previous studies, chemical compositions of atmospheric particles were provided using filter-based offline analyses, which were unable to provide long-term and in-situ measurements that resolve sufficient temp...

Fine particulate matter (PM2.5) is associated with various adverse health outcomes and poses serious concerns for public health. However, ground monitoring stations for PM2.5 measurements are mostly installed in population-dense or urban areas. Thus, satellite retrieved aerosol optical depth (AOD) data, which provide spatial and temporal surrogates...

Soil moisture is one of the important parameters for research in hydrology, meteorology, ecology, agriculture, and drought fields. It also becomes an important factor in wildfire events. Soil moisture monitoring in conventional ways is usually limited in the spatial distribution over a large area. On the other hand, the observation from satellite r...

In 2018, 70% of global fatalities due to pneumonia occurred in about fifteen countries, with Tanzania being among the top eight countries contributing to these deaths. Environmental and individual factors contributing to these deaths may be multifaceted, but they have not yet been explored in Tanzania. Therefore, in this study, we explore the assoc...

Quantifying aerosol compositions (e.g., type, loading) from remotely sensed measurements by spaceborne, suborbital and ground-based platforms is a challenging task. In this study, the first and second-order spectral derivatives of aerosol optical depth (AOD) with respect to wavelength are explored to determine the partitions of the major components...

Globally, it was estimated that maternal and under-five deaths were high in low-income countries than that of high-income countries. Most studies, however, have focused only on the clinical causes of maternal and under-five deaths, and yet there could be other factors such as ambient particulate matter (PM). The current global estimates indicate th...

The vertical distribution of aerosols is important for accurate surface PM2.5 retrieval and initial modeling forecasts of air pollution, but the observation of aerosol profiles on the regional scale is usually limited. Therefore, in this study, an approach to aerosol extinction profile fitting is proposed to improve surface PM2.5 retrieval from sat...

Long-range transport (LRT) of air pollutants from East Asia during the northeast monsoon season impacts several downwind locations. In 2020, the initial COVID-19 lockdowns in China overlapped with Week 3 of the Chinese New Year (CNY) holiday, and an Asian outflow event. Thus, movement of the Chinese populace from city to city was already greatly re...

External exposure to gamma-photon irradiation from soil contamination due to nuclear power plant (NPP) accidents has significant contribution to human radiation exposure in the proximity of the NPP. Detailed absorbed doses in human organs are rarely reported in the literature. We applied the Monte Carlo Neutron Particle (MCNP) transport code to cal...

Thermal infrared (TIR) satellite images are generally employed to retrieve land surface temperature (LST) data in remote sensing. LST data have been widely used in evapotranspiration (ET) estimation based on satellite observations over broad regions, as well as the surface dryness associated with vegetation index. Landsat-8 Operational Land Imager...

An analysis of pollution homogeneity has been conducted to distinguish between remote and local pollution which contributes to month to month changes in aerosol optical depth (AOD) over the Taiwan area. This was carried out using both AERONET measurements at six monitoring sites in Taiwan and NASA MERRA-2 reanalysis, over the 15-year period from 20...

A new Taiwanese satellite, FORMOSAT-5 (FS-5), with a payload remote sensing instrument (RSI) was launched in August 2017 to continue the mission of its predecessor FORMOSAT-2 (FS-2). Similar to FS-2, the RSI provides 2-m resolution panchromatic and 4-m resolution multi-spectral images as the primary payload on FS-5. However, the radiometric propert...

The Asian region is one of the major emission sources of air pollution. Although ambient PM2.5 has been linked to several health risks in high-, low-, and middle-income countries, the further analysis of type impact is still rare but significant. The PM2.5 distribution retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) aerosol opt...

The Tatun Volcanic Group (TVG) in northern Taiwan is the sole volcanic region on the island, with its last eruptive episode around 5,500 years ago. It has been suggested that the TVG retains the capacity for volcanic explosivity which has the potential to devastate the nearby Taipei metropolitan area of 7 million inhabitants. Though the probability...

As the sum of soil evaporation and canopy transpiration, evapotranspiration (ET) can be estimated using land surface heat flux models and land surface temperature (LST) data. Landsat-8 operational land imager (OLI) and thermal infrared (TIR) sensors can provide LST data in 30 m spatial resolution that have been widely used. However, ET estimation r...

Since 1990 the Hanoi capital region (or Hanoi metropolitan area) in Vietnam has undergone rapid development, which has gone together with increasing socioeconomic growth and prosperity. However, the environmental degradation that has accompanied urban development has raised considerable concern from the public in recent years. This research investi...

Radiometric calibration for imaging sensors is a crucial procedure to ensure imagery quality. One of the challenges in relative radiometric calibration is to correct detector-level artifacts due to the fluctuation in discrepant responses (spatial) and electronic instability (temporal). In this paper, the integration of the empirical mode decomposit...

In this study, an approach has been developed for differentiating between local and remote pollution over Taiwan, based on the homogeneity (variations of the standard deviation) of both AERONET measurements and NASA MERRA aerosol reanalysis (version 2, MERRA-2) over a 15-year period (2002–2017). The analysis of seasonal variations of the standard d...

Urban heat island (UHI) is principally caused by the differences in form and composition of atmosphere and land surface related to atmospheric pollutants and land use/land cover (LU-LC) types. As an important part of radiative forcing process, land surfaces have bidirectional interaction with the atmosphere in the planetary boundary layer (PBL). LU...

This study improved significantly the relationship between aerosol optical depth (AOD) and sea surface chlorophyll-a concentration (Chl-a), after considering the effects of sea surface temperature (SST), ocean surface current (OSC) and type of aerosols. The decadal satellite-retrieved Orbview-2/SeaWiFS Chl-a and Terra/MODIS AOD550nm data (from Marc...

This study examined a specific case of planning for policymaking in response to two physical environmental issues: flooding and the urban heat island effect (UHI). The Southern Taiwan Science Park (STSP) was selected as a case study. Data were primarily collected through interviews as well as through policy review. The assessment showed significant...

The present study utilizes air quality modeling to probe the sources and characteristics of PM2.5 (particles less than 2.5 micrometers in aerodynamic diameter) at the northern tip of Taiwan (CAFE station) in the early stage of the Asian haze period. Since CAFE is the first place that is influenced by the Asian haze coming from the north, this study...

This study presents dust event spatiotemporal distribution and regional trends, and the impact of surface wind and precipitation on dust occurrences in Mongolia. We used data collected between 2000 and 2013 from 113 meteorological stations in natural forest steppe, steppe, Gobi Desert, and mountain zones. We analyzed the relationship between dusty...

A record breaking extreme precipitation event produced 3000 mm day⁻¹ of accumulated rainfall over southern Taiwan in August 2009. The interactions between Typhoon Morakot and the prevailing southwesterly (SW) monsoon are the primary mechanism for this heavy precipitation during 5-13 August 2009. This extreme precipitation could be produced by the a...

The Community Multi-scale Air Quality Model (CMAQ) is used to simulate the long-range transport of biomass burning (BB) pollutants from Southeast Asia (SEA) towards the Taiwan Central Mountain Range (CMR) in March and April 2010. The results show that a proportion of the BB plume was blocked and compressed at the windward side of CMR. High-altitude...

In this study, an approach in determining effective mixing weight of soot aggregates from dust–soot aerosols is proposed to improve the accuracy of retrieving properties of polluted dusts by means of satellite remote sensing. Based on a pre-computed database containing several variables (such as wavelength, refractive index, soot mixing weight, sur...

In general, the type of atmospheric aerosols can be efficiently identified with the characteristics of optical properties, such as Ångström exponent (AE) and single scattering albedo (SSA). However, the retrieval of SSA is not frequently available to global area which may cause the difficulty in the identification of aerosol type. Since aerosol opt...

In general, the type of atmospheric aerosols can be efficiently identified with the characteristics of optical properties, such as Ångström exponent (AE) and single scattering albedo (SSA). However, the retrieval of SSA is not frequently available to global area which may cause the difficulty in the identification of aerosol type. Since aerosol opt...

Many people in Asia regions have been suffering from disastrous rainfalls year by year. The rainfall from typhoons or tropical cyclones (TCs) is one of their key water supply sources, but from another perspective such TCs may also bring forth unexpected heavy rainfall, thereby causing flash floods, mudslides or other disasters. So far we cannot sto...

This work examines the permanent aerosol source regions over Asia by analyzing 7-years data of aerosol optical thickness (AOT) product from MODerate Imaging Spectroradiometer (MODIS) onboard Aqua and Terra satellites. The analysis is carried out by taking the average AOT map during the years 2002-2008 over the region in different seasons, in which...

Atmospheric temperature soundings derived from satellite-based advanced infrared (IR) sounder radiance measurements tend to have higher uncertainty in the upper troposphere. In contrast, radio occultation (RO) measurements have high accuracy and high vertical-resolution for atmospheric sounding in the upper troposphere and lower stratosphere (UTLS)...

In this study, the aerosol optical properties and vertical distributions in major biomass-burning emission area of northern Indochina were investigated using ground-based remote sensing (i.e., four Sun-sky radiometers and one lidar) during the Seven South East Asian Studies/Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interact...

This study used the spectral features of the geostationary satellite infrared window channel and the water vapor channel data to calculate a new parameter, normalized difference convection index (NDCI), to help determine the overshooting areas in typhoon cloud systems and the centers and intensity of typhoons. The results showed that the two-dimens...

This paper investigates the aerosol properties over the major East Asian stations of Beijing, Gosan, Osaka, Taipei, Muk-dahan, and Bac-Giang, during the years 2002-2008. Aerosol optical thickness (AOT) product from the moderate resolution imaging spectroradiometers (MODIS) onboard the Aqua and Terra satellites are used for this study. The aerosol r...

By modulating the Earth-atmosphere energy, hydrological and biogeochemical cycles, and affecting regional-to-global weather and climate, biomass burning is recognized as one of the major factors affecting the global carbon cycle. However, few comprehensive and wide-ranging experiments have been conducted to characterize biomass-burning pollutants i...

This study employed data mining techniques to analyze topographic and vegetative factors for the verification of landslides induced by heavy rainfall in a regional scale in Taiwan. Decision Tree and Bayesian Network data mining algorithms were implemented to extract knowledge from supplied landslide factors. Eleven topographic and vegetative factor...

The U.S. Geological Survey (USGS) land use (LU) data employed in the Weather Research and Forecasting (WRF) model classify most LU types in Taiwan as mixtures of irrigated cropland and forest, which is not an accurate representation of current conditions. The WRF model released after version 3.1 provides an alternative LU dataset retrieved from 200...

The effect of black carbon on the optical properties of polluted mineral dust is studied from a satellite remote-sensing perspective. By including the auxiliary data of surface reflectivity and aerosol mixing weight, the optical properties of mineral dust, or more specifically, the aerosol optical depth (AOD) and single-scattering albedo (SSA), can...

Long range transport leads mineral dusts to internally/externally mix with the ambient aerosols, such as soot particles, naturally. The physicochemical characteristics of dust particles thus are dramatically altered after mixing with soot aggregates. Therefore, the investigation on the optical properties of mineral dust along with their pathway cau...

This paper presents a systematic approach to utilize multi-temporal remote sensing images and spatial analysis for the detection, investigation, and long-term monitoring of landslide hazards in Taiwan. Rigorous orthorectification of satellite images are achieved by correction of sensor orbits and backward projections with ground control points of d...

AbSTrAcT Surprisingly, on 27 December 2001, a storm named Typhoon Vamei formed near in Singaporean waters. An examina-tion on the SSM/I-derived rainfall rates and air-sea parameters showed that significant higher latent heat release and air-sea energy flux during convective rainfall activities played a key role in the typhoon's growth. A quantitati...

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument is considered a very versatile tool in studying environmental changes. The multi-spectral sensor owns a high revisit period, a large scanning area, plus a handful of other advantages. The main purpose of this study is to employ reflectance data retrieved by the MODIS sensor in det...

Although typhoon forecasting has been improved notably over the years, it remains a difficult challenge to make timely and accurate rainfall forecasts, which is crucial to saving lives and reducing damage. Under the assumption that a proportional relationship exists between the accumulated rainfall of a typhoon hitting Taiwan and climatological acc...

The Penghu archipelago comprises 64 basaltic volcanic isles lying on the Taiwan Strait between mainland China and Taiwan. The water around and within these isles is shallow and poses considerable difficulty in echo sounding detection for bathymetry. Most existing bathymetry data around such areas are in water depths of greater than 5 m. Therefore,...

This principle focus of this study is the absolute radiometric calibrations of FORMOSAT-2 RSI imagery in orbit. There are two principal parts for achieving this calibration. The first is the assessment of the calibration site by examining atmospheric observations from ground stations and field measurements via ground-based radiometric instruments....

This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved ae...

In general, the topographic effect is particularly evident for steep sloped mountainous terrain. Despite the same land-cover, significant variations between the phototropic and apheliotropic areas can be clearly detected from satellite imagery. Therefore, the consideration of the topographic effect is essential when satellite data is applied in ret...

Landcover information is a critical parameter for environmental assessment but difficult to collect and update using conventional approach. This paper demonstrates a systematic approach of using remote sensing images to distinguish different types of landcover automatically or semi-automatically is a more economical and effective approach for envir...

This study extended the computation of GLCM (gray level co-occurrence matrix) to a three-dimensional form. The objective was to treat hyperspectral image cubes as volumetric data sets and use the developed 3D GLCM computation algorithm to extract discriminant volumetric texture features for classification. As the kernel size of the moving box is th...

This study developed an image integration and classification system in order to provide necessary spatial parameters for an integrated mesoscale environmental assessment system (IMEAS). The lack of complete and up-to-date coverage of landcover/landuse information has reduced the reliability of IMEAS modeling results, especially for the emission mod...

In this study, data provided by the geostationary satellite GMS-5 S-VISSR was used to monitor dust storms. Although other satellites, such as TOMS, provide information regarding dust cover and air quality over specific locations, their limited orbital observation time makes it hard to issue real-time warnings for dust storms. Since geostationary sa...

The improvement in the structure function method for retrieving aerosol optical depth (AOD) with SPOT HRV data and its application in air quality monitoring are highlighted in this paper. Generally speaking, estimation of the aerosol optical depth will be affected by the temporal change of surface canopy, observation geometry and terrain effect whe...