The ground-based observation dataset of aerosol optical properties over the Tibetan Plateau was obtained by continuous observation with a Cimel 318 sunphotometer, involving two stations: Qomolangma Station and Nam Co Station. These products have taken the process of cloud detection. The data cover the period from January 1, 2021 to December 31, 2021, and the time resolution is daily. The sunphotometer has eight observation channels from visible light to near infrared, and the central wavelengths are 340, 380, 440, 500, 670, 870, 940 and 1120 nm, respectively. The field of view angle of the instrument is 1.2°, and the sun tracking accuracy is 0.1°. Six bands of aerosol optical thickness can be obtained from direct solar radiation, and the accuracy is estimated to be 0.01-0.02. Finally, AERONET unified inversion algorithm was used to obtain the aerosol optical thickness, Ångström index, aerosol particle size distribution, single scattering albedo, phase function, complex refraction index and asymmetry factor.
CONG Zhiyuan
The aerosol optical thickness data of the Arctic Alaska station is formed based on the observation data products of the US Department of Energy's atmospheric radiation observation program at the Arctic Alaska station. The data coverage time is from 1998 to 2020, the time resolution is hourly, the coverage site is the Arctic Alaska station, and the longitude and latitude coordinates are (71 ° 19 ′ 22.8 ″ N, 156 ° 36 ′ 32.4 ″ W). The observation data is obtained from the inversion of the radiation data observed by MFRSR instrument. The optical characteristic variable is aerosol optical thickness, and the observation inversion error range is about 15%. The data format is nc format.
ZHAO Chuanfeng
The 0.1 º aerosol optical thickness dataset (also known as the "Poles AOD Collection 1.0" aerosol optical thickness (AOD) dataset) in the polar regions from 2000 to 2020 was produced by combining Merra-2 mode data and MODIS satellite sensor AOD. The data covers the period from 2000 to 2020, with a daily time resolution, covering the "tri polar" (Antarctic, Arctic and Qinghai Tibet Plateau) region, and a spatial resolution of 0.1 degree. The verification of the measured stations shows that the relative deviation of the data is within 35%, which can effectively improve the coverage and accuracy of AOD in the polar region.
GUANG Jie GUANG Jie
Aerosol Optical Depth (AOD) reflects the attenuation of solar radiation to the surface by aerosols. The aerosol type is calculated according to the aerosol optical thickness (AOD). This data set is derived from the latest MODIS aerosol secondary product MOD04_ L2 and MYD04_ L2, where MOD and MYD represent Terra and Aqua satellites respectively. At present, MODIS aerosol retrieval algorithms are Dark Target (DT) and Deep Blue (DB). According to the inversion accuracy of the metadata field table Quality Assurance Confidence (QAC), DT and DB algorithm products are integrated to deal with land, ocean and coast respectively. The index quality is optimal (QAF=3) or suboptimal (QAF=2) or meets the basic needs (QAF=1) to obtain high-resolution AOD products (0.1 degree, daily scale) with full coverage and long time series. According to AOD experience threshold (AOD: 0~0.2, clean type; 0.2~0.6, urban or industrial type; greater than 0.6, sand dust type) The aerosol types are classified into three types: clean type (1), urban or industrial type (2) and sand dust type (3). This dataset provides MOD, MYD and fusion products based on transit time.
YE Aizhong
Aerosol Optical Depth (AOD) reflects the attenuation of solar radiation to the surface by aerosols. This data set is derived from the latest MODIS aerosol secondary product MOD04_ L2 and MYD04_ L2, where MOD and MYD represent Terra and Aqua satellites respectively. At present, MODIS aerosol retrieval algorithms are Dark Target (DT) and Deep Blue (DB). According to the inversion accuracy of the metadata field table Quality Assurance Confidence (QAC), DT and DB algorithm products are integrated to deal with land, ocean and coast respectively. The index quality is optimal (QAF=3) or suboptimal (QAF=2) or meets the basic needs (QAF=1) to obtain high-resolution AOD products (0.1 degree, daily scale) with full coverage and long time series. This dataset provides MOD, MYD and fusion products based on transit time.
YE Aizhong
1) The optical depth, vertical mass concentration and extinction coefficient of dust, sulfate, organic carbon, black carbon and sea salt aerosols and total aerosols were measured; 2) Data source: numerical simulation, processing method: Based on CALIPSO satellite vertical observation and global aerosol model, it is generated by four-dimensional local ensemble transformation Kalman filter assimilation method; 3) The data quality is good; 4) It can also be used to study the spatiotemporal distribution of aerosols and their spatial and temporal characteristics of precipitation and their assimilation.
DAI Tie, CHENG Yueming
There are two types of aerosol data in the Tibetan Plateau. Aerosol type data products are the results of aerosol type data fusion by using Meera 2 assimilation data and active satellite CALIPSO products through a series of data preprocessing, quality control, statistical analysis and comparative analysis. The key of the algorithm is to judge the CALIPSO aerosol type. According to CALIPSO aerosol types and quality control, and referring to merra 2 aerosol types, the final aerosol type data (12 kinds) and quality control results were obtained. Considering the vertical and spatial distribution of aerosols, it has high spatial resolution (0.625 ° × 0.5 °) and temporal resolution (month). Aerosol optical depth (AOD) is a visible band remote sensing inversion method developed by ourselves, combined with merra-2 model data and NASA's official product mod04. The data coverage time is from 2000 to 2019, with daily temporal resolution and spatial resolution of 0.1 degree. The retrieval method mainly uses the self-developed APRs algorithm to retrieve the aerosol optical depth over the ice and snow. The algorithm takes into account the BRDF characteristics of the ice and snow surface, and is suitable for the inversion of aerosol optical thickness on the ice and snow. The results show that the relative deviation of the data is less than 35%, which can effectively improve the coverage and accuracy of the polar AOD.
GUANG Jie, ZHAO Chuanfeng
This dataset includes the concentrations and spatial pattern of organic carbon (OC) and Elemental carbon (EC) in the carbonaceous aerosol (CA) of the Tibetan Plateau and surroundings. OC and EC were measured by Desert Research Institute Model 2001 Thermal/Optical Carbon Analyzer. The limit of detection (LOD) for OC and EC were 0.43 and 0.12 ug/cm2, respectively. In addition, MAC was also calculated for assessing the effect of EC. This dataset will provide the informations of CA contamination and background values over the Tibetan Plateau and surroundings.
The three pole aerosol type data product is an aerosol type result obtained by integrating the data assimilation of Meera 2 and the active satellite CALIPSO product through a series of data preprocessing, quality control, statistical analysis and comparative analysis. The key of this algorithm is to judge the type of CALIPSO aerosol. In the process of aerosol type data fusion, according to the type and quality control of CALIPSO aerosol, and referring to the type of merra 2 aerosol, the final aerosol type data (12 kinds in total) and quality control results in the three pole area are obtained. The data product fully considers the vertical distribution and spatial distribution of aerosols, with high spatial resolution (0.625 ° × 0.5 °) and time resolution (month).
ZHAO Chuanfeng
The "poles AOD Collection 1.0" aerosol optical thickness (AOD) data set adopts the self-developed visible band remote sensing inversion method, combined with the merra-2 model data and the official NASA product mod04. The data covers from 2000 to 2019, with the time resolution of day by day, covering the "three poles" (Antarctic, Arctic and Qinghai Tibet Plateau) area, and the spatial resolution of 0.1. Degree. The inversion method mainly uses the self-developed APRs algorithm to invert the aerosol optical thickness over ice and snow. The algorithm considers the BRDF characteristics of ice and snow surface, and is suitable for the inversion of aerosol optical thickness over ice and snow. The experimental results show that the relative deviation of the data is less than 35%, which can effectively improve the coverage and accuracy of the aerosol optical thickness in the polar region.
GUANG Jie
The aerosol optical thickness data of Qomolangma station and Namuco station in the Qinghai Tibet Plateau is based on the observation data products of Qomolangma station and Namuco station from the atmospheric radiation view of the Institute of Qinghai Tibet Plateau of the Chinese Academy of Sciences. The data coverage time is from 2017 to 2019, the time resolution is hour by hour, the coverage sites are Qomolangma station and Namuco station, the longitude and latitude coordinates are (Qomolangma station: 28.365n, 86.948e, Namuco station Mucuo station: 30.7725n, 90.9626e). The source of the observed data is retrieved from the radiation data observed by mfrsr instrument. The characteristic variable is aerosol optical thickness, and the error range of the observed inversion is about 15%. The data format is TXT.
CONG Zhiyuan
The total solar radiation and the total radiation of absorption and scattering material attenuation are measured by the international general solar radiation meter (li200sz, li-cor, Inc., USA). The measured data are total solar radiation, including direct and diffuse solar radiation, with a wavelength range of 400-1100nm. The unit of measurement is w / m2, and the typical error is ± 3% (incidence angle is within 60 °) under natural lighting. The data of sodankyl ä station in the Arctic comes from cooperation with the site and website download. The coverage time of sodankyl ä station in the Arctic is updated to 2018.
BAI Jianhui
The aerosol optical thickness data of the Arctic Alaska station is based on the observation data products of the atmospheric radiation observation plan of the U.S. Department of energy at the Arctic Alaska station. The data coverage time is updated from 2016 to 2019, with the time resolution of hour by hour. The coverage site is the northern Alaska station, with the longitude and latitude coordinates of (71 ° 19 ′ 22.8 ″ n, 156 ° 36 ′ 32.4 ″ w). The source of the observed data is retrieved from the radiation data observed by mfrsr instrument. The characteristic variable is aerosol optical thickness, and the error range of the observed inversion is about 15%. The data format is NC format.
ZHAO Chuanfeng
As the “water tower of Asia”, Tibetan Plateau (TP) are the resource of major rivers in Asia. Black carbon (BC) aerosol emitted from surrounding regions can be transported to the inner TP by atmospheric circulation and consequently deposited in snow, which can significantly influence precipitation and mass balance of glaciers. Five Aethalometers are used to mornitoring black carbon concentration at 5 stations on the Tibetan Plateau. It can provide basic dataset to study the effects of BC to the environment and climate over the Tibetan Plateau, as well as the pollutants transport.
Wildfires can strongly affect the frozen soil environment by burning surface vegetation and soil organic matter. Vegetation affected by fire can take many years to return to mature pre-fire levels. In this data set, the effects of fires on vegetation regrowth in a frozen-ground tundra environment in the Anaktuvuk River Basin on the North Slope of Alaska were studied by quantifying changes in C-band and L-band SAR backscatter data over 15 years (2002-2017). After the fire, the C- and L-band backscattering coefficients increased by 5.5 and 4.4 dB, respectively, in the severe fire area compared to the unburned area. Five years after the fire, the difference in C-band backscattering between the fire zone and the unburned zone decreased, indicating that the post-fire vegetation level had recovered to the level of the unburned zone. This long recovery time is longer than the 3-year recovery estimated from visible wavelength-based NDVI observations. In addition, after 10 years of vegetation recovery, the backscattering of the L-band in the severe fire zone remains approximately 2 dB higher than that of the unburned zone. This continued difference may be caused by an increase in surface roughness. Our analysis shows that long-term SAR backscattering data sets can quantify vegetation recovery after fire in an Arctic tundra environment and can also be used to supplement visible-wavelength observations. The temporal coverage of the backscattering data is from 2002 to 2017, with a time resolution of one month, and the data cover the Anaktuvuk River area on the North Slope of Alaska. The spatial resolution is 30~100 m, the C- and L-band data are separated, and a GeoTIFF file is stored every month. For details on the data, see SAR Backscattering Data of the Anaktuvuk River Basin on the North Slope of Alaska - Data Description.
JIANG Liming
The measurement data of the sun spectrophotometer can be directly used to perform inversion on the optical thickness of the non-water vapor channel, Rayleigh scattering, aerosol optical thickness, and moisture content of the atmospheric air column (using the measurement data at 936 nm of the water vapor channel). The aerosol optical property data set of the Tibetan Plateau by ground-based observations was obtained by adopting the Cimel 318 sun photometer, and both the Mt. Qomolangma and Namco stations were involved. The temporal coverage of the data is from 2009 to 2016, and the temporal resolution is one day. The sun photometer has eight observation channels from visible light to near infrared. The center wavelengths are 340, 380, 440, 500, 670, 870, 940 and 1120 nm. The field angle of the instrument is 1.2°, and the sun tracking accuracy is 0.1°. According to the direct solar radiation, the aerosol optical thickness of 6 bands can be obtained, and the estimated accuracy is 0.01 to 0.02. Finally, the AERONET unified inversion algorithm was used to obtain aerosol optical thickness, Angstrom index, particle size spectrum, single scattering albedo, phase function, birefringence index, asymmetry factor, etc.
CONG Zhiyuan
The “China Collection 1.0" aerosol optical depth (AOD) data set was produced using visible light wave remote sensing inversion. The raw data come from the MODIS sensors on Terra and Aqua. The temporal coverage of the data is from 2002 to 2011, the temporal resolution is daily, the spatial coverage is the Asian continent, and the spatial resolution is 0.1°. The remote sensing inversion method uses the independently developed SRAP algorithm to invert the aerosol optical depth over the land. The algorithm takes the BRDF characteristics of the surface into consideration, which makes it applicable to aerosol optical depth inversion on bright and dark surfaces. In addition, aerosol products over the ocean of MOD04/MYD04 are superimposed. The verification of the measured site shows that the relative deviation of the aerosol optical depth data in Asia is within 20%. The data are stored as an hdf file each day, each consisting of Terra AOD and Aqua AOD at 550 nm.
GUANG Jie, XUE Yong
The aerosol optical thickness data of the Arctic Alaska station is based on the observation data products of the atmospheric radiation observation plan of the U.S. Department of energy at the Arctic Alaska station. The data coverage time is from 1998 to 2016, and the time resolution is hour by hour. The coverage site is the Arctic Alaska station, with the longitude and latitude coordinates of (71 ° 19 ′ 22.8 ″ n, 156 ° 36 ′ 32.4 ″ w). The source of the observed data is retrieved from the radiation data observed by mfrsr instrument. The optical characteristic variable is aerosol optical thickness, and the error range of the observed inversion is about 15%. The data format is NC format.
ZHAO Chuanfeng
The object of this dataset is to support the atmospheric correction data for the satellite and airborne remote-sensing. It provides the atmospheric aerosol and the column content of water vapor. The dataset is sectioned into two parts: the conventional observations data and the observations data synchronized with the airborne experiments. The instrument was on the roof of the 7# in the Wuxing Jiayuan community from 1 to 24 in June. After 25 June, it was moved to the ditch in the south of the Supperstaiton 15. The dataset provide the raw observations data and the retrieval data which contains the atmosphere aerosol optical depth (AOD) of the wavebands at the center of 1640 nm, 1020 nm, 936 nm, 870 nm, 670 nm, 500 nm, 440 nm, 380 nm and 340 nm, respectively, and the water vapor content is retrieved from the band data with a centroid wavelength of 936 nm. The continuous data was obtained from the 1 June to 20 September in 2012 with a one minute temporal resolution. The time used in this dataset is in UTC+8 Time. Instrument: The sun photometer is employed to measure the character of atmosphere. In HiWATER, the CE318-NE was used.
YU Wenping, WANG Zengyan, MA Mingguo
The dataset of sun photometer observations was obtained in the Yingke oasis and Huazhaizi desert steppe foci experimental areas. 24 times observations were carried out by CE318 from BNU (at 1020nm, 936nm, 870nm, 670nm and 440nm, and column water vapor by 936 nm data) and from Institute of Remote Sensing Applications, CAS (at 1640nm, 1020nm, 936nm, 870nm, 670nm, 550nm, 440nm, 380nm and 340nm, and column water vapor by 936 nm data) on May 20, 23, 25 and 27, Jun. 4, 6, 16, 20, 22, 23, 27 and 29, Jul. 1, 7 and 11, 2008. Those atmospheric measurements synchronized with airborne (i.e. WiDAS, OMIS) and spaceborne sensors (i.e. TM, ASTER,CHRIS and Hyperion) Accuracy of CE318 could be influenced by local air pressure, instrument calibration parameters, and convertion factors. (1) Most air pressure was derived from elevation-related empiricism, which was not reliable. For more accurate result, simultaneous data from the weather station are needed. (2) Errors from instrument calibration parameters. Field calibration based on Langly or interior instrument calibrationcin the standard light is required. (3) Convertion factors for retrieval of aerosol optical depth and the water vapor of the water vapor channel were also from empiricism, and need further checking. Raw data were archived in k7 format and can be opened by ASTPWin. ReadMe.txt is attached for details. Preprocessed data (after retrieval of the raw data) in Excel format are on optical depth, Rayleigh scattering, aerosol optical depth, the horizontal visibility, the near surface air temperature, the solar azimuth, zenith, solar distance correlation factors, and air column mass number. Langley was used for the instrument calibration. Two parts are included in CE318 result data (see Geometric Positions and the Total Optical Depth of Each Channel and Rayleigh Scattering and Aerosol Optical Depth of Each Channel).
REN Huazhong, YAN Guangkuo, GUANG Jie, SU Gaoli, WANG Ying, ZHOU Chunyan
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