Thread: Re: Alaska TA station L18K data gaps & number of traces

Hi Melody,

Sorry for the slow reply, I'm not sure what happened to your earlier message but I will look into that.

Regarding the gaps, that's outside of our domain -- we just archive the data and don't really have visibility into the source. The AK network is operated by the Alaska Earthquake Center at University of Alaska Fairbanks (http://earthquake.alaska.edu/), you would probably need to contact them to get any details on that.

(I do know that Covid-related travel restrictions caused problems for a lot of remote instruments, because technicians had no way to get to the physical site for maintenance and repairs.)

Cheers,
Adam

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Adam Clark
Web Application Developer
IRIS Data Management Center
adam<at>iris.washington.edu

On Nov 1, 2021, at 10:51 AM, Melody Zhang (via IRIS) <message-center-bounce<at>lists.ds.iris.edu> wrote:

Hi there,

Three weeks ago, I emailed both the IRIS Data Processing Help and Data Request Help about gaps between the traces I was downloading from the Vaisala weather station on L18K in the Alaska Transportable Array. (See previous message for details.) I have not heard anything back and am therefore emailing again.

Thanks,

Mel Zhang (张) How to pronounce my name https://nmdrp.me/melzhang
Pronouns: she/her
PhD student, Geophysics
Colorado School of Mines sits upon the traditional lands of the Ute and Cheyenne peoples. Further, I acknowledge that 48 contemporary tribal nations https://www.colorado.gov/pacific/ccia/historic-tribes-colorado are historically tied to lands that make up the state of Colorado.
From: Melody Zhang
Sent: Monday, October 11, 2021 7:45 PM
To: data-processing-help<at>lists.ds.iris.edu <data-processing-help<at>lists.ds.iris.edu> <data-processing-help<at>lists.ds.iris.edu <data-processing-help<at>lists.ds.iris.edu>>
Cc: data-request-help<at>lists.ds.iris.edu <data-request-help<at>lists.ds.iris.edu> <data-request-help<at>lists.ds.iris.edu <data-request-help<at>lists.ds.iris.edu>>; Valerie Sahakian <vjs<at>uoregon.edu <vjs<at>uoregon.edu>>
Subject: Alaska TA station L18K data gaps & number of traces

Hi there,
I have a question about the data gaps I'm seeing once I have my traces downloaded.

I use TA data for my PhD thesis research. I'm working with the wind speed and rain intensity (LWS and LRO channels) data from station L18K https://ds.iris.edu/mda/AK/L18K/ in the TA deployed in Alaska. I use a Python script to query IRIS, build the two channels' data streams and merge all traces in the stream. Looking at data from a single year, Jan 1-Dec 31, 2020, I've wound up with 405 discrete traces. Merging them into one trace works, and so does plotting the data. I've attached a text doc showing start/end times for a big portion of the traces for LWS. I also attached my timeseries plot.

It seemed peculiar to me that there are so many interruptions often resulting in multiple traces in a single day, and thatthere are also large gaps with no data for many days at a time. I'm not sure if this is because the instrument is losing and re-establishing connections, and it certainly doesn't seem like it's due to instrument maintenance/replacement. It's also peculiar that the largest gaps are around summer, when the Vaisala instrument was anticipated to have data gaps during winter (according to Tytell et al., 2016 https://journals.ametsoc.org/view/journals/bams/97/4/bams-d-14-00204.1.xml?tab_body=pdf).

I've been discussing it with my collaborator Val Sahakian (cc'ed), who hasn't experienced these issues when working with the seismic channels. I'm wondering if anyone can offer an explanation or has investigated these aspects of the data before.

Sincerely
Mel Zhang

Mel Zhang (张) How to pronounce my name https://nmdrp.me/melzhang
Pronouns: she/her
PhD student, Geophysics
Colorado School of Mines sits upon the traditional lands of the Ute and Cheyenne peoples. Further, I acknowledge that 48 contemporary tribal nations https://www.colorado.gov/pacific/ccia/historic-tribes-colorado are historically tied to lands that make up the state of Colorado.

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