[ncl-talk] Problems on Reading Satellite Date

Dennis Shea shea at ucar.edu
Sun Jun 11 21:43:44 MDT 2017


Please *look* at your file dump. In particular, look at the variable types
(integer, short) and the scale_factor and add_offset attributes.

See attached.
===========
There are numerous satellite swath examples:

https://www.ncl.ucar.edu/Applications/HDF.shtml

Good luck


On Sun, Jun 11, 2017 at 1:30 AM, 宫明晓 <gongmingxiao1988 at 163.com> wrote:

> Dear NCL team,
>
>    I have read a satellite grid data, but  I want to read the data on the
> fixed longitude and latitude, so I need to change the data from data(
> NUMROWS, NUMCELLS) to data(lat,lon), how can I do it?
> Sorry my English is very poor.
> Thank you very much!
>
>
> ;;-------------------------------------------------------------
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> ;;------------------------------------------------------------------------
>
> f=addfile("ascat_20130416_134200_metopa_33683_eps_o_coa_2101_ovw.l2.nc
> ","r")
> u_speed=f->wind_speed
> vs = new(dimsizes(f->wind_speed),float,-99999)
> vs =(f->wind_speed)*0.01
>
> lat2d = f->lat
> lon2d = f->lon
> lat2d at units = "degrees_north"
> lon2d at units = "degrees_east"
>
> vs at lat2d          = lat2d
> vs at lon2d        = lon2d
> vs at units          =    "ms-1"
> vs at coordinmates      = "lat2d lon2d"
>
> print(vs({11},{11}))  ;;;*how can I print the data like this type??????*
>
>
>
>
> *;;PrintVarSummary(f)*
>
> Variable: f
> Type: file
> filename: ascat_20130416_134200_metopa_33683_eps_o_coa_2101_ovw.l2
> path: ascat_20130416_134200_metopa_33683_eps_o_coa_2101_ovw.l2.nc
>   file global attributes:
>      title : MetOp-A ASCAT Level 2 Coastal Ocean Surface Wind Vector
> Product
>      title_short_name : ASCAT-L2-Coastal
>      Conventions : CF-1.4
>      institution : EUMETSAT/OSI SAF/KNMI
>      source : MetOp-A ASCAT
>      software_identification_level_1 : 801
>      instrument_calibration_version : 0
>      software_identification_wind : 2101
>      pixel_size_on_horizontal : 12.5 km
>      service_type : eps
>      processing_type : O
>      contents : ovw
>      granule_name : ascat_20130416_134200_metopa_
> 33683_eps_o_coa_2101_ovw.l2.nc
>      processing_level : L2
>      orbit_number : 33683
>      start_date : 2013-04-16
>      start_time : 13:42:00
>      stop_date : 2013-04-16
>      stop_time : 15:23:58
>      equator_crossing_longitude :  116.924
>      equator_crossing_date : 2013-04-16
>      equator_crossing_time : 13:41:03
>      rev_orbit_period : 6081.7
>      orbit_inclination : 98.7
>      history : N/A
>      references : ASCAT Wind Product User Manual, http://www.osi-saf.org/,
> http://www.knmi.nl/scatterometer/
>      comment : Orbit period and inclination are constant values. All wind
> directions in oceanographic convention (0 deg. flowing North)
>      creation_date : 2013-04-16
>      creation_time : 16:27:43
>   dimensions:
>      NUMROWS = 3259
>      NUMCELLS = 82
>   variables:
>      integer time ( NUMROWS, NUMCELLS )
>         _FillValue : -2147483647 <(214)%20748-3647>
>         missing_value : -2147483647 <(214)%20748-3647>
>         valid_min : 0
>         valid_max : 2147483647 <(214)%20748-3647>
>         long_name : time
>         units : seconds since 1990-01-01 00:00:00
>         coordinates : lat lon
>
>      integer lat ( NUMROWS, NUMCELLS )
>         _FillValue : -2147483647 <(214)%20748-3647>
>         missing_value : -2147483647 <(214)%20748-3647>
>         valid_min : -9000000
>         valid_max : 9000000
>         long_name : latitude
>         units : degrees_north
>         scale_factor : 1e-05
>         add_offset :   0
>
>      integer lon ( NUMROWS, NUMCELLS )
>         _FillValue : -2147483647 <(214)%20748-3647>
>         missing_value : -2147483647 <(214)%20748-3647>
>         valid_min : 0
>         valid_max : 36000000
>         long_name : longitude
>         units : degrees_east
>         scale_factor : 1e-05
>         add_offset :   0
>
>      short wvc_index ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : 0
>         valid_max : 999
>         long_name : cross track wind vector cell number
>         units : 1
>         coordinates : lat lon
>
>      short model_speed ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : 0
>         valid_max : 5000
>         long_name : model wind speed at 10 m
>         units : m s-1
>         scale_factor : 0.01
>         add_offset :   0
>         coordinates : lat lon
>
>      short model_dir ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : 0
>         valid_max : 3600
>         long_name : model wind direction at 10 m
>         units : degree
>         scale_factor : 0.1
>         add_offset :   0
>         coordinates : lat lon
>
>      short ice_prob ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : 0
>         valid_max : 1000
>         long_name : ice probability
>         units : 1
>         scale_factor : 0.001
>         add_offset :   0
>         coordinates : lat lon
>
>      short ice_age ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : -5000
>         valid_max : 5000
>         long_name : ice age (a-parameter)
>         units : dB
>         scale_factor : 0.01
>         add_offset :   0
>         coordinates : lat lon
>
>      integer wvc_quality_flag ( NUMROWS, NUMCELLS )
>         _FillValue : -2147483647 <(214)%20748-3647>
>         missing_value : -2147483647 <(214)%20748-3647>
>         valid_min : 0
>         valid_max : 8388607
>         long_name : wind vector cell quality
>         coordinates : lat lon
>         flag_masks : <ARRAY of 17 elements>
>         flag_meanings : distance_to_gmf_too_large data_are_redundant
> no_meteorological_background_used rain_detected rain_flag_not_usable
> small_wind_less_than_or_equal_to_3_m_s large_wind_greater_than_30_m_s
> wind_inversion_not_successful some_portion_of_wvc_is_over_ice
> some_portion_of_wvc_is_over_land variational_quality_control_fails
> knmi_quality_control_fails product_monitoring_event_flag
> product_monitoring_not_used any_beam_noise_content_above_threshold
> poor_azimuth_diversity not_enough_good_sigma0_for_wind_retrieval
>
>
>
>
>
>
>
>
>
>
> *      short wind_speed ( NUMROWS, NUMCELLS )         _FillValue : -32767
>         missing_value : -32767         valid_min : 0         valid_max :
> 5000         long_name : wind speed at 10 m         units : m s-1
>         scale_factor : 0.01         add_offset :   0         coordinates :
> lat lon*
>
>      short wind_dir ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : 0
>         valid_max : 3600
>         long_name : wind direction at 10 m
>         units : degree
>         scale_factor : 0.1
>         add_offset :   0
>         coordinates : lat lon
>
>      short bs_distance ( NUMROWS, NUMCELLS )
>         _FillValue : -32767
>         missing_value : -32767
>         valid_min : -500
>         valid_max : 500
>         long_name : backscatter distance
>         units : 1
>         scale_factor : 0.1
>         add_offset :   0
>         coordinates : lat lon
>
>
>
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