[ncl-talk] Wrong values getting on contour plot

Barry Lynn barry.h.lynn at gmail.com
Thu Jun 4 13:26:38 MDT 2020 

The data you are reading has a certain grid spacing. If it is too large,
grid point values will not be representative of the observed mlsp. Also, if
this forecast data, the forecast could just be wrong.

On Thu, 4 Jun 2020 at 22:22 Arathy RP <arathyrparathy at gmail.com> wrote:

> Actually i am not understanding what u meant by gridspacing.I didn't put
> anything related to grid spacing.
>
> On Thu, Jun 4, 2020 at 5:48 PM Arathy RP <arathyrparathy at gmail.com> wrote:
>
>> Yes, that's it.
>>
>> On Fri, Jun 5, 2020 at 12:47 AM Barry Lynn <barry.h.lynn at gmail.com>
>> wrote:
>>
>>> The data set itself?
>>>
>>> On Thu, 4 Jun 2020 at 22:13 Arathy RP <arathyrparathy at gmail.com> wrote:
>>>
>>>> Actually there is no gridlines used know. Its just a simple contour
>>>> plot know.
>>>>
>>>> On Thu, Jun 4, 2020 at 5:38 PM Arathy RP <arathyrparathy at gmail.com>
>>>> wrote:
>>>>
>>>>> What do you mean?
>>>>>
>>>>> On Fri, Jun 5, 2020 at 12:37 AM Barry Lynn <barry.h.lynn at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> What is the grid spacing of the data?
>>>>>>
>>>>>> On Thu, Jun 4, 2020 at 9:50 PM Arathy RP <arathyrparathy at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> and the location is correct.
>>>>>>>
>>>>>>> On Thu, Jun 4, 2020 at 5:19 PM Arathy RP <arathyrparathy at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> hi
>>>>>>>> Actually the exact time which i want to get minimum pressure is 32
>>>>>>>> .But i am getting on 36th timestep only minimum value.
>>>>>>>>
>>>>>>>> On Fri, Jun 5, 2020 at 12:11 AM Barry Lynn <barry.h.lynn at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Hi:
>>>>>>>>>
>>>>>>>>> Making progress.
>>>>>>>>>
>>>>>>>>> Is that the location and time when you expect the lowest pressure?
>>>>>>>>>
>>>>>>>>> On Thu, 4 Jun 2020 at 20:46 Arathy RP <arathyrparathy at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> here is the printvarsummary of variable f
>>>>>>>>>> Variable: f
>>>>>>>>>> Type: float
>>>>>>>>>> Total Size: 462720 bytes
>>>>>>>>>>             115680 values
>>>>>>>>>> Number of Dimensions: 2
>>>>>>>>>> Dimensions and sizes: [g0_lat_1 | 241] x [g0_lon_2 | 480]
>>>>>>>>>> Coordinates:
>>>>>>>>>>             g0_lat_1: [90..-90]
>>>>>>>>>>             g0_lon_2: [ 0..359.25]
>>>>>>>>>> Number Of Attributes: 11
>>>>>>>>>>   initial_time0_hours : 1873944
>>>>>>>>>>   center : European Center for Medium-Range Weather Forecasts
>>>>>>>>>> (RSMC)
>>>>>>>>>>   long_name : Mean sea level pressure
>>>>>>>>>>   units : Pa
>>>>>>>>>>   _FillValue : 1e+20
>>>>>>>>>>   level_indicator : 1
>>>>>>>>>>   gds_grid_type : 0
>>>>>>>>>>   parameter_table_version : 128
>>>>>>>>>>   parameter_number : 151
>>>>>>>>>>   forecast_time : 0
>>>>>>>>>>   forecast_time_units : hours
>>>>>>>>>> And here is the printvarsummary of f_sub
>>>>>>>>>> Variable: f_sub
>>>>>>>>>> Type: float
>>>>>>>>>> Total Size: 14472 bytes
>>>>>>>>>>             3618 values
>>>>>>>>>> Number of Dimensions: 2
>>>>>>>>>> Dimensions and sizes: [g0_lat_1 | 54] x [g0_lon_2 | 67]
>>>>>>>>>> Coordinates:
>>>>>>>>>>             g0_lat_1: [ 0..39.75]
>>>>>>>>>>             g0_lon_2: [60..109.5]
>>>>>>>>>> Number Of Attributes: 11
>>>>>>>>>>   forecast_time_units : hours
>>>>>>>>>>   forecast_time : 0
>>>>>>>>>>   parameter_number : 151
>>>>>>>>>>   parameter_table_version : 128
>>>>>>>>>>   gds_grid_type : 0
>>>>>>>>>>   level_indicator : 1
>>>>>>>>>>   _FillValue : 1e+20
>>>>>>>>>>   units : Pa
>>>>>>>>>>   long_name : Mean sea level pressure
>>>>>>>>>>   center : European Center for Medium-Range Weather Forecasts
>>>>>>>>>> (RSMC)
>>>>>>>>>>   initial_time0_hours : 1873944
>>>>>>>>>> (0) Mean sea level pressure (Pa) : min=99429.4   max=102977
>>>>>>>>>>
>>>>>>>>>> On Thu, Jun 4, 2020, 12:04 PM Barry Lynn <barry.h.lynn at gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi:
>>>>>>>>>>>
>>>>>>>>>>> You need to reply to all, or they will get lost.
>>>>>>>>>>>
>>>>>>>>>>> What do you imply by "mean sea level pressure?"  Do you imply
>>>>>>>>>>> that the pressure is averaged?
>>>>>>>>>>>
>>>>>>>>>>> It is not hard to find the minimum in an data field, so please
>>>>>>>>>>> just clarify and I will try to help you.
>>>>>>>>>>>
>>>>>>>>>>> It is hard for me to correct other people's code, but I can send
>>>>>>>>>>> you code that should work to identify the minimum sea level pressure, or at
>>>>>>>>>>> least help you to adapt your own.
>>>>>>>>>>>
>>>>>>>>>>> Barry
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Jun 4, 2020 at 9:20 AM Arathy RP <
>>>>>>>>>>> arathyrparathy at gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hi,
>>>>>>>>>>>> Actually i want to get the minimum value for mean sea level
>>>>>>>>>>>> pressure and I didn't understand the purpose for defining area .
>>>>>>>>>>>> Can you please show an example.
>>>>>>>>>>>>
>>>>>>>>>>>> On Thu, Jun 4, 2020, 12:45 AM Barry Lynn <
>>>>>>>>>>>> barry.h.lynn at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Hi:
>>>>>>>>>>>>>
>>>>>>>>>>>>> If you are plotting mean sea level pressure, you need to
>>>>>>>>>>>>> define over what area you calculate the mean. Otherwise, your mean will
>>>>>>>>>>>>> encompass an area much larger than the storm's center.
>>>>>>>>>>>>>
>>>>>>>>>>>>> For instance, you could calculate the mean in areas where the
>>>>>>>>>>>>> wind speed is greater than some value, using the "where" statement.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Do you do that?
>>>>>>>>>>>>>
>>>>>>>>>>>>> Barry
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 9:50 PM Arathy RP <
>>>>>>>>>>>>> arathyrparathy at gmail.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>> Yes, I will do that.
>>>>>>>>>>>>>> Actually I am plotting mean sea level pressure of very severe
>>>>>>>>>>>>>> cyclonic storm Phailin.And I want to get the minimum mean sea level
>>>>>>>>>>>>>> pressure as 994.29Pa only. As the cyclone belongs to category 5 storm the
>>>>>>>>>>>>>> pressure level should go beyond 960Pa so that intensified contour plot of
>>>>>>>>>>>>>> Phailin i will get. And the code is written by me by refering ncl sites.
>>>>>>>>>>>>>> I hereby attach the variable details and minimum pressure
>>>>>>>>>>>>>> showing when plotted.
>>>>>>>>>>>>>> Thanking you
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 8:31 PM Barry Lynn <
>>>>>>>>>>>>>> barry.h.lynn at gmail.com> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Hi:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Can you show us what you are getting and what pressure you
>>>>>>>>>>>>>>> print out as the center pressure.  This would help identify the problem.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Also, where did you get the code to make the surface
>>>>>>>>>>>>>>> pressure maps/tracking? Can you define what you mean by minimum contour
>>>>>>>>>>>>>>> plot.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Barry
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 4:27 PM Arathy RP via ncl-talk <
>>>>>>>>>>>>>>> ncl-talk at ucar.edu> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>>>> I am arz student of MSc finally year . As a part of my
>>>>>>>>>>>>>>>> project work , i am working with cyclone contour plotting.I am dealing with
>>>>>>>>>>>>>>>> cyclone phailin and i want to get minimum value contour plot for mean sea
>>>>>>>>>>>>>>>> level pressure of cyclone.Actually there is no error showing even though i
>>>>>>>>>>>>>>>> am getting a wrong value. I can't find what wrong with this .can you please
>>>>>>>>>>>>>>>> help me to clarify it.
>>>>>>>>>>>>>>>> I am dealing with an intensified cyclone plot but not
>>>>>>>>>>>>>>>> getting a result as expected. Please help me.
>>>>>>>>>>>>>>>> I hereby attaching the data and ncl script used.
>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>> ncl-talk mailing list
>>>>>>>>>>>>>>>> ncl-talk at ucar.edu
>>>>>>>>>>>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>>>>>>>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> --
>>>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>>>
>>>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>
>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>
>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>> Weather and Climate Focus
>>>>>>>>> http://weather-it-is.com
>>>>>>>>> Jerusalem, Israel
>>>>>>>>> Local: 02 930 9525
>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>
>>>>>>>>>
>>>>>>
>>>>>> --
>>>>>> Barry H. Lynn, Ph.D
>>>>>> Senior Associate Scientist, Lecturer,
>>>>>> The Institute of the Earth Science,
>>>>>> The Hebrew University of Jerusalem,
>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>> Tel: 972 547 231 170
>>>>>> Fax: (972)-25662581
>>>>>>
>>>>>> C.E.O, Weather It Is, LTD
>>>>>> Weather and Climate Focus
>>>>>> http://weather-it-is.com
>>>>>> Jerusalem, Israel
>>>>>> Local: 02 930 9525
>>>>>> Cell: 054 7 231 170
>>>>>> Int-IS: x972 2 930 9525
>>>>>>
>>>>>> --
>>> Barry H. Lynn, Ph.D
>>> Senior Associate Scientist, Lecturer,
>>> The Institute of the Earth Science,
>>> The Hebrew University of Jerusalem,
>>> Givat Ram, Jerusalem 91904, Israel
>>> Tel: 972 547 231 170
>>> Fax: (972)-25662581
>>>
>>> C.E.O, Weather It Is, LTD
>>> Weather and Climate Focus
>>> http://weather-it-is.com
>>> Jerusalem, Israel
>>> Local: 02 930 9525
>>> Cell: 054 7 231 170
>>> Int-IS: x972 2 930 9525
>>>
>>> --
Barry H. Lynn, Ph.D
Senior Associate Scientist, Lecturer,
The Institute of the Earth Science,
The Hebrew University of Jerusalem,
Givat Ram, Jerusalem 91904, Israel
Tel: 972 547 231 170
Fax: (972)-25662581

C.E.O, Weather It Is, LTD
Weather and Climate Focus
http://weather-it-is.com
Jerusalem, Israel
Local: 02 930 9525
Cell: 054 7 231 170
Int-IS: x972 2 930 9525
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