Re: [python-users] Siphon/MetPy: Invalid height data read from U of Wyoming RAOBs

• To: Geoffrey Lewen <geoffreylewen@xxxxxxxxx>
• Subject: Re: [python-users] Siphon/MetPy: Invalid height data read from U of Wyoming RAOBs
• From: Ryan May <rmay@xxxxxxxx>
• Date: Tue, 23 May 2023 13:39:21 -0600

Greetings!

Thanks for the report. It looks like the problem is that this sounding has
a lot of levels, which pushes the larger height values beyond the 100 rows
that `pandas.read_fwf()` uses by default to autodetect appropriate column
widths. This has been fixed in https://github.com/Unidata/siphon/pull/696,
which will be released with siphon 0.9.1 (release date TBD). In the
meantime, if you need the fix available sooner, you can install siphon
directly from git with:

pip install git+https://github.com/Unidata/siphon

Cheers!

Ryan

On Mon, May 22, 2023 at 11:24 PM Geoffrey Lewen <geoffreylewen@xxxxxxxxx>
wrote:

> Hello,
>
> I recently encountered a situation in which the data returned by Siphon’s
> client for the University of Wyoming Upper Air archive contained invalid
> height data. (Please see below.)
>
> Thanks for any assistance or advice with this issue,
>
> Geoff
>
>
>
> -------------------------------------------------------------------------------
>
> SUMMARY:    This involves the 5/22/2023 12Z RAOB for station OUN.  The
> heights appeared to be the "actual heights modulo 10km”.   The data in
> the U of Wyoming web form does not show any issue, nor is there a problem
> with the height when using Siphon to read the sounding from Iowa State.
>
> My MetPy/Siphon environment is
>
> •   MetPy 1.5.0
> •   Siphon 0.9
>
>
> Here is a simple example of code to reproduce the situation:
>
>
> -------------------------------------------------------------------------------
>
> from datetime import datetime
> import matplotlib.pyplot as plt
> import numpy as np
> from siphon.simplewebservice.wyoming import WyomingUpperAir
>
> Year = 2023
> Month = 5
> Day = 22
> Hour = 12
> date=datetime(Year,Month,Day,Hour)
> station = 'OUN'
>
> #  Read height data
> df = WyomingUpperAir.request_data(date, station)
> Z1 = df['height'].values
>
> #  Data extracted manually from the University of Wyoming Web form
>
> WebForm = np.array([  345,   397,   440,   493,   537,   564,   635,
> 716,   779,
>          806,   870,   880,   907,   963,  1028,  1075,  1094,  1122,
>         1170,  1208,  1227,  1266,  1295,  1324,  1421,  1471,  1520,
>         1540,  1822,  1863,  1966,  2019,  2103,  2720,  2879,  2925,
>         3097,  3132,  3261,  3356,  3392,  3416,  3452,  3536,  3561,
>         3609,  3658,  3832,  3920,  4072,  4227,  4292,  4410,  4450,
>         4477,  4517,  4584,  4611,  4624,  4705,  4954,  5067,  5110,
>         5153,  5181,  5326,  5385,  5414,  5518,  5577,  5592,  5607,
>         5623,  5683,  5698,  5759,  5790,  5976,  6262,  6391,  6506,
>         6523,  6589,  6656,  6774,  6911,  6962,  7014,  7032,  7067,
>         7102,  7119,  7137,  7261,  7279,  7297,  7333,  7369,  7442,
>         7460,  7478,  7534,  7645,  7683,  7701,  7739,  7834,  8065,
>         8085,  8104,  8144,  8203,  8243,  8322,  8383,  8423,  8444,
>         8464,  8650,  8713,  8839,  8882,  8946,  8989,  9142,  9186,
>         9341,  9409,  9432,  9454,  9477,  9500,  9523,  9754,  9801,
>         9872,  9968, 10040, 10138, 10187, 10336, 10512, 10720, 10800,
>        10907, 10934, 10988, 11015, 11070, 11407, 11465, 11581, 11640,
>        11880, 11911, 11942, 12003, 12066, 12160, 12286, 12351, 12416,
>        12754, 13112, 13611, 13814, 13980, 14421, 14607, 15094, 15352,
>        15564, 15784, 15896, 16068, 16550])
>
> #  Simple plot of the data.  The third plot shows the "modulo 10k" of the
> Webform data for comparison.
>
> fig, axes = plt.subplots(nrows=1, ncols=3, figsize=(10, 5))
> axes[0].plot(z1)
> axes[0].set_title('UWYO-siphon')
> axes[1].plot(WebForm)
> axes[1].set_title('UWYO-WebForm')
> axes[2].plot(WebForm % 10000)
> axes[2].set_title('WebForm modulo 10k')
> fig.tight_layout()
>
>
> -------------------------------------------------------------------------------
>
> Output:
>
>
> [image: +P88Jbv7ya7TIAAAAAElFTkSuQmCC.png]
>
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-- 
Ryan May
Unidata Deputy Director
UCAR
Boulder, CO

• References:
  • [python-users] Siphon/MetPy: Invalid height data read from U of Wyoming RAOBs
    • From: Geoffrey Lewen