P-Tree System
(Answer) Due to the system constraints, only those observed during 00 to 09 minutes per hour are shown for images that has passed over 3 months from the observations, and others are removed from the web server. Note that all the physical products can be obtained from the ftp site (including those data taken during 10-59 minutes). Note that geophysical products of all past periods are available via FTP in NetCDF format. |
(Answer) We provide you the geostationary satellite Himawari Standard Data provided by the Japan Meteorological Agency (JMA) as well as the geophysical parameter data produced by JAXA using the Himawari Standard Data via our FTP site. Request your account from here. |
(Answer) No major web browser accept you to access FTP sites. Use FTP client software, such as FileZilla or WinSCP. |
(Answer) May we ask you to register again? |
(Answer) Our FTP server limits the number of simultaneous connections. You can simultaneously download data up to 30 connections from a host or 100 hosts. |
(Answer) When a server trouble occurs, we will announce in What's New. Network traffic might be temporarily very busy. Try to access later. If data down load delays to long time, contact us. |
(Answer) The Himawari Standard Data(HSD) is the most closest data to raw data and is the data with the largest amount of information among the Himawari observation data provided from the Japan Meterology Agency (JMA). JAXA disseminates the HSD data to users for non-profit purposes such as research and education based on cooperative agreement with JMA. For details on the HSD data, please refer to the following URLs. - Himawari Standard Data (Meteorological Satellite Center of JMA) - Himawari Standard Data User's Guide |
(Answer) Due to system constraints, those data that has passed over 30 days has been deleted from the P-Tree FTP server. The other services distributing the Himawari Original Data are listed below. Please contact the administrator of each sites for further details. - World Science Data Bank by NICT - Data Integration and Analysis System (DIAS) by the University of Tokyo |
(Answer) NetCDF is a self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The detail of the NetCDF can be found in the following URL: https://www.unidata.ucar.edu/software/netcdf/ |
(Answer) Use the programming languages (C, FORTRAN, C++, Java, etc.) with including the NetCDF libraries, which are freely distributed from the NetCDF official website. As a GUI-based software, the 'hdfview' is also useful to access There are also some other commercial software that support the NetCDF. |
(Answer) Please refer the following websites and references. - JAXA Himawari Monitor Aerosol Products - References (L2 Aerosol Algorithm) Yoshida, M, M. Kikuchi, T. M. Nagao, H. Murakami, T. Nomaki, and A. Higurashi, 2018: Common retrieval of aerosol properties for imaging satellite sensors, J. Meteor. Soc. Japan, doi:10.2151/jmsj.2018-039. https://www.jstage.jst.go.jp/article/jmsj/advpub/0/advpub_2018-039/_article/-char/en. (L3 Hourly Aerosol Algorithm) Kikuchi, M., H. Murakami, K. Suzuki, T. M. Nagao, and A. Higurashi, Improved Hourly Estimates of Aerosol Optical Thickness using Spatiotemporal Variability Derived from Himawari-8 Geostationary Satellite, IEEE Transactions on Geoscience and Remote Sensing, accepted. |
(Answer) ATBD has not been published for Himawari products. See our User’s guide as well as documents and references. |
(Answer) The format of SST product conforms to Group for High Resolution Sea Surface Temperature (GHRSST) format instead of other Himawari products. |
(Answer) No. We distribute top of atmosphere (TOA) reflectance without atmospheric correction. We define albedo as reflectance*cos(SOZ), where SOZ is solar zenith angle, for Himawari product. |
(Answer) No. The HImawari-8 L1 data is projected onto the WGS84 ellipsoid without orthorectification. Therefor ground elevation and cloud height are not corrected. |
(Answer) The solar azimuth angle ranges from -180 to 180 degree. When you want them ranging from 0 to 360 degree, follow as following. From 0 to 180 degree, you can use the azimuth angle without any correction. From -180 to 0 degree, just add 360 degree to convert them into the range of 180 to 360 degree. |
(Answer) The artifact on the Chlorophyll a product is attributed to the pixel to pixel sensitivity variation of the scan unit of the AHI sensor, which is calibrated within the sensor spec. The slight difference between the pixel sensitivity can be emphasized after the atmospheric correction. This stripe noise is noticeable over daily and monthly products because temporal averaging reduce the other noises but the difference between the pixel sensitivity remains. |
(Answer) The cloud property retrieval relies on a lookup table of cloud optical thickness and effective particle radius calculated by radiative transfer simulation. The cloud retrieval algorithm flag would be 011=Failed when the retrieval algorithm could not find optimal solution which occurs when cloud is extremely thin or thick, land surface was coverd by ice/snow, or the pixel was corresponding to sunglint. When the flag was 011=Failed, check an additional flag, namely, (4,3) Cloud Mask Confidence Level Flag: 00=Clear, 01=Probably Clear, 10=Probably Cloudy, 11=Cloudy; If the ""011=Failed"" occurred over the pixels with very thick cloud (perhaps, the Cloud Mask Confidence Level Flag=11), you should treat the pixel as cloud. However, when the ""011=Failed"" occurred on the edge of cloud or thick aerosol, the Cloud Mask Confidence Level Flag is usually 10=Probably Cloudy. In such case, the pixel is ambiguous to be cloudy or not." |
(Answer) The release timing of the Level 3 aerosol product is generally 2 and half hours to 6 hours from the observation. The algorithm to generate the Level 2 aerosol product sacrificed processing time to improve the accuracy. Usually it takes 2 to 5 hours from the observation to process the Level 2 aerosol product. Then the Level 3 aerosol products are generally created 2 and half hours to 6 hours from the observation because the Level 3 products are created based on the Level 2 products during one hour. |
(Answer) The observation time contained in the file names time is in UTC. Convert to your local time. |
(Answer) The parameter "AOT_Merged_uncertainty" is a unitless and you can write the uncertainty as the following: "AOT_Merged" ± "AOT_Merged_uncertainty" |
(Answer) The level 3 daily data are created from the Level 2 product at 00:00 to 23:50 UTC. |
(Answer) The Chlorophyll-a concentrations represents the depth of about 0 to few m depending on the transmittance of the water, which generally increases from coastal to open ocean. Subsurface chlorophyll-a is not detected over subtropical stratified ocean. |
(Answer) The full-disk Himawari L1 Gridded Data covers 60S-60N, 80E-160W in 0.02 degree resolution. You can convert x, y in the image to longitude and latitude as longitude = 80 + x * 0.02 latitude = 60 - y * 0.02 Or, you can retrieve latitude and longitude table from the netCDF file by using software to treat netCDF format. |
(Answer) Use the scale factor and add offset stored in NetCDF file to obtain the physical quantity. For bands 1 to 6, the scale factor and add offset are 0.0001 and 0.0. For bands 7 to 16, the scale factor and add offset are 0.01 and 273.15. |
(Answer) See the document of Meteorological Satellite Center. |
(Answer) No. CLP cannot be calculated without solar radiance. |
(Answer) The level 3 hourly data are created from the Level 2 product on the hour to 50 minutes past the hour. The time in the file name indicates the beginning of the period. |
(Answer) Use of the data provided from the system is limited to non-profit purposes such as research and education based on the policy of the JMA. For profit or business purposes, please contact the Japan Meteorological Business Support Center. |