[TangerineSDR] Fwd: another 24hour RM3100 run and comparison with Fredericksburg

Tue Sep 15 15:38:47 EDT 2020

Frequent Y-axis offset is not surprising as X and Y are quite
susceptible to geospace environment.  Of course, the Z axis not being well
leveled is a different story.

[image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
Assistant Professor
Physics
Center for Solar-Terrestrial Research
Institute for Space Weather Sciences
hmkim at njit.edu • (973) 596-5704
https://web.njit.edu/~hmkim/
104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102

On Tue, Sep 15, 2020 at 3:20 PM Julius Madey <hillfox at fairpoint.net> wrote:

> Hyomin, that's good news.  I know you've been busy.   I also have to check
> alignment of the in ground RM3100; the PVC pipe may have shifted slightly
> as the soil around it settles.  When first installed, the Yaxis was almost
> zero but is now a bit off; the Z axis may be slightly off as well ...
> alignment was using a spirit level on a machinist's square.
>
>
> On 9/15/2020 1:24 PM, Kim, Hyomin wrote:
>
> Jules - the mag is under test at this moment. Hopefully, I can give some
> updates soon.
>
>
>
> [image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
> Assistant Professor
> Physics
> Center for Solar-Terrestrial Research
> Institute for Space Weather Sciences
> hmkim at njit.edu • (973) 596-5704
> https://web.njit.edu/~hmkim/
> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>
>
> On Tue, Sep 15, 2020 at 12:43 PM Julius Madey <hillfox at fairpoint.net>
> wrote:
>
>> The Z axis reading is high relative to the Z axis value of 48,032.0nT
>> from the World Magnetic Model for that day for my specific location of
>> 42deg 15min 41.24sec North, 73deg 32min 32.43sec West, 1220 ft elevation.
>>
>> Hyomin, have you had time to complete the solenoid coil measurement of
>> the RM3100?
>>
>> Jules - K2KGJ
>>
>>
>> On 9/15/2020 11:58 AM, Kim, Hyomin wrote:
>>
>> Just to add to Phil's comments, what I see from the Z axis (if I am not
>> wrong), is that there is a drift (whether real or not) in our Z axis data:
>> for example, Bz in the USGS mag began at ~0 nT and ended at ~0 nT whereas
>> ours began at ~49980 nT and ended at 50000 nT, which is a 20 nT increase.
>>
>>
>>
>> [image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
>> Assistant Professor
>> Physics
>> Center for Solar-Terrestrial Research
>> Institute for Space Weather Sciences
>> hmkim at njit.edu • (973) 596-5704
>> https://web.njit.edu/~hmkim/
>> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>
>>
>> On Tue, Sep 15, 2020 at 11:53 AM Phil Erickson <phil.erickson at gmail.com>
>> wrote:
>>
>>> Hi David,
>>>
>>>   When I say "secular change", I meant the time scale of the change.
>>> Secular = long term, in this case relative to the time scales of a magnetic
>>> disturbance.  For example, storm time current variations might occur on a
>>> few minute to hour or two scale, but would not last for 24 hours.  The
>>> latter is what I was referring to and indicates a more long term drift.  If
>>> you saw that drift for example from day to day, that is now climatology
>>> (not weather) and you would have to see whether that is reasonable
>>> geophysically.
>>>
>>> 73
>>> Phil
>>>
>>> On Tue, Sep 15, 2020 at 11:50 AM David Witten <wittend at wwrinc.com>
>>> wrote:
>>>
>>>> Phil, Hyomin,
>>>>
>>>> I believe that I understand your comments, but to be sure, may I ask
>>>> exactly what is meant by 'secular change'.  I do not want to make incorrect
>>>> assumptions about a term of art.
>>>>
>>>> Dave
>>>>
>>>> On Tue, Sep 15, 2020 at 10:45 AM Phil Erickson <phil.erickson at gmail.com>
>>>> wrote:
>>>>
>>>>> If it is picking up a 10 nT level secular change, that is fabulous for
>>>>> a reasonable cost sensor!  Maybe Jules has a ground induced current
>>>>> nearby?  Anyhow, temperature sensitivity at a more precise level is I'm
>>>>> sure all part of the calibration needs, so we'll find out later...
>>>>>
>>>>> Phil
>>>>>
>>>>> On Tue, Sep 15, 2020 at 11:40 AM Kim, Hyomin <hmkim at njit.edu> wrote:
>>>>>
>>>>>> Ah, yes I agree - the secular change seems to be a little off. I
>>>>>> paid more attention to the small scale variations which look to be
>>>>>> similar. This is a mystery to me. Maybe our sensor is not so precisely
>>>>>> calibrated, say, to ambient temperature or something? Or we found another
>>>>>> magnetic anomaly near where Jules lives!!
>>>>>>
>>>>>>
>>>>>> [image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
>>>>>> Assistant Professor
>>>>>> Physics
>>>>>> Center for Solar-Terrestrial Research
>>>>>> Institute for Space Weather Sciences
>>>>>> hmkim at njit.edu • (973) 596-5704
>>>>>> https://web.njit.edu/~hmkim/
>>>>>> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>>>>>
>>>>>>
>>>>>> On Tue, Sep 15, 2020 at 11:34 AM Phil Erickson <
>>>>>> phil.erickson at gmail.com> wrote:
>>>>>>
>>>>>>> Hi Hyomin,
>>>>>>>
>>>>>>>  You have a more expert eye than I do, so I read your statements as
>>>>>>> "uncalibrated axes", which of course is entirely correct for this RM3100
>>>>>>> data.  I just don't know how to separate the geophysical (latitudinal
>>>>>>> difference) from the instrumental (positional axes are not exactly the
>>>>>>> same).  I was reacting mostly to the 24 hour secular change in each
>>>>>>> component.  Is it reasonable to assume that is much less sensitive for
>>>>>>> horizontal vs vertical components?
>>>>>>>
>>>>>>> 73
>>>>>>> Phil
>>>>>>>
>>>>>>> On Tue, Sep 15, 2020 at 11:27 AM Kim, Hyomin <hmkim at njit.edu> wrote:
>>>>>>>
>>>>>>>> Hi Phil,
>>>>>>>> At a first glance I thought the Z traces matched well as the
>>>>>>>> relative values appear to be similar in that axis. If I am not wrong, Bz is
>>>>>>>> oriented toward the center of the earth for the USGS mags. I believe the
>>>>>>>> USGS mag is quite precisely oriented whereas our mag is not. Thus any
>>>>>>>> slight offset in orientation can be seen noticeably as Bz has the biggest
>>>>>>>> values? Also, the latitudinal difference between his place and
>>>>>>>> Fredericksburg could be another factor?
>>>>>>>>
>>>>>>>> Hyomin
>>>>>>>>
>>>>>>>> [image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
>>>>>>>> Assistant Professor
>>>>>>>> Physics
>>>>>>>> Center for Solar-Terrestrial Research
>>>>>>>> Institute for Space Weather Sciences
>>>>>>>> hmkim at njit.edu • (973) 596-5704
>>>>>>>> https://web.njit.edu/~hmkim/
>>>>>>>> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>>>>>>>
>>>>>>>>
>>>>>>>> On Tue, Sep 15, 2020 at 10:39 AM Phil Erickson via TangerineSDR <
>>>>>>>> tangerinesdr at lists.tapr.org> wrote:
>>>>>>>>
>>>>>>>>> Hi Dave,
>>>>>>>>>
>>>>>>>>>   The X and Y traces return after 24 hours to nearly the same
>>>>>>>>> relative value in both the reference and RM3100 traces.  The Z trace does
>>>>>>>>> not.  Ionospheric currents flowing in the E region should not affect Z
>>>>>>>>> exclusive of X and Y under most any geometry I can think of, so I wondered
>>>>>>>>> whether the uncalibrated RM3100 was likely causing this.  (I have never
>>>>>>>>> professionally calibrated a magnetometer, so Hyomin might need to comment
>>>>>>>>> here.). In other words, I always assume there is some measurement
>>>>>>>>> systematic until it has been completely ruled out before assigning it to
>>>>>>>>> geophysical variation.
>>>>>>>>>
>>>>>>>>> 73
>>>>>>>>> Phil W1PJE
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Tue, Sep 15, 2020 at 10:34 AM David Witten <wittend at wwrinc.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> @Phil,
>>>>>>>>>>
>>>>>>>>>> Correlation is great, and surely some further calibration issues
>>>>>>>>>> may remain.  But these sensors are NOT colocated - (200-300+ mi apart?) .
>>>>>>>>>> Wouldn't it be suspicious if they did correlate perfectly?  If they did,
>>>>>>>>>> shouldn't  we ask if we do really need an extensive array of these
>>>>>>>>>> sensors?  Presumably there will always be some local variation at this
>>>>>>>>>> scale?  (don't know, just asking)
>>>>>>>>>>
>>>>>>>>>> Dave Witten, KD0EAG
>>>>>>>>>>
>>>>>>>>>> On Tue, Sep 15, 2020 at 7:21 AM Phil Erickson <
>>>>>>>>>> phil.erickson at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi all,
>>>>>>>>>>>
>>>>>>>>>>>   There appears to be a 10 nT drift in the Z component for the
>>>>>>>>>>> RM3100 that is not in the Fredericksburg traces.  Is that slow systematic
>>>>>>>>>>> bias expected?  Maybe things are not calbrated over that time frame quite
>>>>>>>>>>> yet?
>>>>>>>>>>>
>>>>>>>>>>> 73
>>>>>>>>>>> Phil W1PJE
>>>>>>>>>>>
>>>>>>>>>>> On Mon, Sep 14, 2020 at 10:49 PM David Witten via TangerineSDR <
>>>>>>>>>>> tangerinesdr at lists.tapr.org> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> I don't believe that my previous post carried the file K2KGJ
>>>>>>>>>>>> provided.
>>>>>>>>>>>>
>>>>>>>>>>>> ---------- Forwarded message ---------
>>>>>>>>>>>> From: Julius Madey <hillfox at fairpoint.net>
>>>>>>>>>>>> Date: Mon, Sep 14, 2020 at 4:26 PM
>>>>>>>>>>>> Subject: another 24hour RM3100 run and comparison with
>>>>>>>>>>>> Fredericksburg
>>>>>>>>>>>> To: Kim, Hyomin <hmkim at njit.edu>, David Witten <
>>>>>>>>>>>> wittend at wwrinc.com>, Dr. Nathaniel A. Frissell Ph.D. <
>>>>>>>>>>>> nathaniel.frissell at scranton.edu>, Dave Larsen <
>>>>>>>>>>>> kv0s.dave at gmail.com>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> All,
>>>>>>>>>>>> I was hoping to record a relatively short term event but missed
>>>>>>>>>>>> one about 10 days ago.  However, there was a good run on the 12th with an
>>>>>>>>>>>> ~30nT excursion on the Y axis lasting about an hour.  In the attached pdf,
>>>>>>>>>>>> the three axes of the RM3100 again track the Fredericksburg magnetometer
>>>>>>>>>>>> station data quite closely.  The RM3100 plotted data points are simple
>>>>>>>>>>>> running 60second averages and not the more complex filtering algorithm used
>>>>>>>>>>>> by Intermagnet stations for their 1 minute data points.
>>>>>>>>>>>>
>>>>>>>>>>>> The vertical axes scales on all plots are as close as I could
>>>>>>>>>>>> match them by eye in cutting and pasting.
>>>>>>>>>>>>
>>>>>>>>>>>> I believe the value to the right on the Intermagnet plot is the
>>>>>>>>>>>> mean for the 24 hour period.  I did not try to compute a 24 hour mean.
>>>>>>>>>>>>
>>>>>>>>>>>> One of the products for the future for general interest would
>>>>>>>>>>>> be a running plot like those available on Intermagnet.org.  I guess we can
>>>>>>>>>>>> dream a bit.
>>>>>>>>>>>>
>>>>>>>>>>>> Jules - K2KGJ
>>>>>>>>>>>> --
>>>>>>>>>>>> TangerineSDR mailing list
>>>>>>>>>>>> TangerineSDR at lists.tapr.org
>>>>>>>>>>>>
>>>>>>>>>>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> ----
>>>>>>>>>>> Phil Erickson
>>>>>>>>>>> phil.erickson at gmail.com
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> ----
>>>>>>>>> Phil Erickson
>>>>>>>>> phil.erickson at gmail.com
>>>>>>>>> --
>>>>>>>>> TangerineSDR mailing list
>>>>>>>>> TangerineSDR at lists.tapr.org
>>>>>>>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> ----
>>>>>>> Phil Erickson
>>>>>>> phil.erickson at gmail.com
>>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> ----
>>>>> Phil Erickson
>>>>> phil.erickson at gmail.com
>>>>>
>>>>
>>>
>>> --
>>> ----
>>> Phil Erickson
>>> phil.erickson at gmail.com
>>>
>>
>>
>
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