= ir2_20190413_Horinouchi2017-Peralta2018 Cloud motion vectors obtained from IR2 nightside images (2.26um) used in published papers Released on 2019-04-13 to the Akatsuki Science Working Team members Produced by: Takeshi Horinouchi = Source data and tool - Source of the data: - IR2 L2 data of internal release version 0.2.1 (Note: L3 data product was not used; bore-sight correction was done separately) - Tool used to derive cloud motion vector - Cloud tracking program: al3ct v1.0 hgtag:6c2f21377e68fc783a76f848d958332f0586f739 == Contents File size File name md5sum 1.3M concat_226_nt3_eps20_pphvlen2.nc 5c79e55e2aba953caf7737a86a992492 856K concat_226_nt4_eps20_pphvlen2.nc e10962625dd7ddf630e6827da851667e File name convention: concat_WWW_ntN_epsXX_pphvlenY.nc nt = 3 or 4 : the number of images used to track clouds (e.g., when 3, three 2-hourly images over 4 hours) WWW = 226 : IR2 filter wavelength (2.26 um) XX = 20 : Value of the precision screening parameter epsilon in Ikegawa and Horinouchi (m/s) Y = 2 : The value of alpha in Horinouchi et al (2017a) == Description Cloud tracking was conducted by using an automated method described in [1] Ikegawa and Horinouchi (2016) and [2] Horinouchi et al (2017a). Its basic algorithm and quality evaluation method are presented in Ikegawa and Horinouchi (2016), and a further improvement and the data screening method are described in [2] Horinouchi et al (2017a). The data in this directory were produced for and used in [4] Peralta et al (2018), by using the same parameters and bore-sight correction in Horinouchi et al (2017b). == References If you write a paper by using the data, please cite the following three papers ([1] and [2] for the methods and [3] for the bore-sight correction and parameter settings) and the data set [5]. Please see [4] too. [1] Ikegawa, S., and T. Horinouchi (2016), Improved automatic estimation of winds at the cloud top of Venus using superposition of cross-correlation surfaces, Icarus, 271, 98-119, https://doi.org/10.1016/j.icarus.2016.01.018 [2] Horinouchi, T., S. Murakami T. Kouyama, K. Ogohara, A. Yamazaki, M. Yamada, and S. Watanabe (2017), Image velocimetry for clouds with relaxation labeling based on deformation consistency, Measurement Science and Technology, 28(8), 085301 (10pp), https://doi.org/10.1088/1361-6501/aa695c [3] Horinouchi, T., S. Murakami, T. Satoh, J. Peralta, K. Ogohara, T. Kouyama, T. Imamura, H. Kashimura, S. S. Limaye, M. Nakamura, T. M. Sato, K. Sugiyama, M. Takagi, S. Watanabe, M. Yamada, A. Yamazaki, E. F. Young (2017), Equatorial jet in the lower to middle cloud layer of Venus revealed by Akatsuki, Nature Geoscience, 10, 646-651, https://doi.org/10.1038/ngeo3016. [4] Peralta, J., Muto, K., Hueso, R., Horinouchi, T., S«”nchez-Lavega, A., Murakami, S. Y., ... & Sagawa, H. (2018), Nightside Winds at the Lower Clouds of Venus with Akatsuki/IR2: Longitudinal, Local Time, and Decadal Variations from Comparison with Previous Measurements, The Astrophysical Journal Supplement Series, 239(2), 29, https://doi.org/10.3847/1538-4365/aae844 [5] Horinouchi, T., S. Murakami, K. Ogohara, T. Kouyama, M. Takagi (2021), Venus Climate Orbiter Akatsuki Cloud Motion Vector Data Set v1.0, JAXA Data Archives and Transmission System, https://doi.org/10.17597/isas.darts/vco-00020 == File contents summary "ncdump -h" output: $ ncdump -h concat_226_nt3_eps20_pphvlen2.nc netcdf concat_226_nt3_eps20_pphvlen2 { dimensions: longitude = 120 ; latitude = 60 ; time = 83 ; variables: float longitude(longitude) ; longitude:long_name = "longitude" ; longitude:units = "degrees_east" ; float latitude(latitude) ; latitude:long_name = "latitude" ; latitude:units = "degrees_north" ; double time(time) ; time:long_name = "observation time" ; time:units = "hours since 2000-1-1 00:00:00 UTC" ; time:comment = "average of time variables in input L3a files" ; double lon_lt0(time) ; lon_lt0:long_name = "longitude where LT=0" ; lon_lt0:units = "degrees_east" ; float U(time, latitude, longitude) ; U:long_name = "zonal velocity" ; U:units = "m s-1" ; U:missing_value = -6.e+36f ; U:coordinates = "lon_lt0" ; float V(time, latitude, longitude) ; V:long_name = "meridional velocity" ; V:units = "m s-1" ; V:missing_value = -6.e+36f ; V:coordinates = "lon_lt0" ; float C(time, latitude, longitude) ; C:long_name = "max. correlation coeff." ; C:units = "1" ; C:missing_value = -999.f ; C:coordinates = "lon_lt0" ; float eps(time, latitude, longitude) ; eps:long_name = "estimated accuracy of the winds" ; eps:units = "m s-1" ; eps:missing_value = -6.e+36f ; eps:coordinates = "lon_lt0" ; float epsu(time, latitude, longitude) ; epsu:long_name = "max(eps1u,eps2u)" ; epsu:units = "m s-1" ; epsu:missing_value = -6.e+36f ; epsu:coordinates = "lon_lt0" ; float epsv(time, latitude, longitude) ; epsv:long_name = "max(eps1v,eps2v)" ; epsv:units = "m s-1" ; epsv:missing_value = -6.e+36f ; epsv:coordinates = "lon_lt0" ; float S_SOLLON(time) ; S_SOLLON:long_name = "sub solar longitude" ; S_SOLLON:units = "degrees_east" ; S_SOLLON:comment = "L2 attribute" ; float S_SOLLAT(time) ; S_SOLLAT:long_name = "sub solar latitude" ; S_SOLLAT:units = "degrees_north" ; S_SOLLAT:comment = "L2 attribute" ; float S_SSCLON(time) ; S_SSCLON:long_name = "AKATSUKI sub S/C longitude" ; S_SSCLON:units = "degrees_east" ; S_SSCLON:comment = "L2 attribute" ; float S_SSCLAT(time) ; S_SSCLAT:long_name = "AKATSUKI sub S/C latitude" ; S_SSCLAT:units = "degrees_north" ; S_SSCLAT:comment = "L2 attribute" ; float S_SSCLT(time) ; S_SSCLT:long_name = "AKATSUKI sub S/C local time" ; S_SSCLT:units = "hours" ; S_SSCLT:comment = "L2 attribute" ; float S_TGRADI(time) ; S_TGRADI:long_name = "target radius at sub S/C point" ; S_TGRADI:units = "km" ; S_TGRADI:comment = "L2 attribute" ; float S_DIST(time) ; S_DIST:long_name = "distance between S/C and Venus" ; S_DIST:units = "km" ; S_DIST:comment = "L2 attribute" ; float S_VSDIST(time) ; S_VSDIST:long_name = "Venus-Sun distance" ; S_VSDIST:units = "km" ; S_VSDIST:comment = "L2 attribute" ; float S_CLDALT(time) ; S_CLDALT:long_name = "assumed cloud altitude" ; S_CLDALT:units = "km" ; S_CLDALT:comment = "L2 attribute" ; // global attributes: :history = "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote U\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote V\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote C\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote eps\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote epsu\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote epsv\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_SOLLON\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_SOLLAT\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_SSCLON\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_SSCLAT\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_SSCLT\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_TGRADI\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_DIST\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_VSDIST\n", "2019-04-13 15:31:17 JST horinout> concat_cmv.rb wrote S_CLDALT" ; }