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Contents

Ground-Based Measurements

(10 minutes)

Learning Objectives:

• Become familiar with which measurements are core validation/calibration data sets

• Know the sampling strategy and naming conventions for each campaign

• Learn where to find and search for SnowEx data

Data Descriptions

What ground-based data sets are central for all field campaigns?

Figure 1. Ground-based measurements central to the SnowEx campaigns. (L) Snow Pit: Observer measures the stratigraphy in the snow pit. (M) Depth Transects: Observer uses the MagnaProbe to measure snow depths. (R). Interval Boards: Observer stomps down the snow to place the interval board for another weekly long measurement cycle.

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What is a snow pit? ⇨ ‘Layer data’ & ‘Site data’ in the SnowEx database

A snow pit is a vertical profile of snow from the snow surface to the ground. This is where we collect a suite of ground observations that aid instrument and model development.

What are depth transects (spirals)? or simply depths ⇨ ‘Point data’ in the SnowEx database

These are point meausurements that tell you how deep the snow is at georeferenced locations. There are several instruments available to capture snow depth, some of which are an avalanche probe, MagnaProbe, or Mesa2.

What is an interval board? ⇨ soon to be ‘Point data’ in the SnowEx database

An interval board is a 2x2” board with a vertical pole attached at the center. The board surface is our reference to track the amount of new snow that falls between field visits. The board remains fixed for the season, and gets cleared each visit.

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Additional detail on what’s in a snow pit

Figure 2. Description of parameters that come from a single snow pit visit. The colored ovals on the images correspond to the colored measurements on the left side.

Explore more detail in the 2020 Experimental Plan

Data Collection

Field note photos from one pit visits. We call these Pit Sheets.

Figure 3. Front and back of the pit sheet field forms. These have largely remained the same throughout the different campaigns. The middle image is a reference for the codes used in the Stratigraphy measurements.

Why do we care about observations from snow pits and other measurements?

• 90% because we need to validate what we see from airborne and satellite sensors!!

• 10% because we are geoscientists that want to winter recreate!!

(You can argue those percentages over our movement / coffee break)

Figure 4. Examples of snow properties and features that are sensitive to modeling and remote sensing signals.

Sampling Strategy and Naming Conventions

2020 Grand Mesa IOP

Figure 5 Nine-member snow and vegetation matrix used to sample and name snow pits during the Grand Mesa IOP campaign

Vegetation Classes

• 1-3 = treeless (0% tree cover)

• 4-6 = sparse (1-30% tree cover)

• 7-9 = dense (31-100% tree cover)

Snow Depth Classes

• 1, 4, 7 = shallow (<90cm)

• 2, 5, 8 = medium (90-122cm)

• 3, 6, 9 = deep (>122cm)

Flight Lines

• ‘C’ = Crossline

• ‘N’ = North

• ‘S’ = South

Figure 6. Grand Mesa IOP 2020 sampling design. The rectangles are the lidar, UAVSAR, SWESARR, Thermal IR, and Gamma flight lines. The point markers are the locations of snow pits.

2020 & 2021 Time Series

• Location ⇨ Regional Location with existing long-term monitoring infrastructure.

• Site ⇨ Averaged unique snow pit site to represent the progression of Time Series snow pits.

• PitID ⇨ 6-letter code unique to all snow pit sites; 2-letter state, 2-letter Location; 2-letter site name (e.g Idaho, Boise River, Bogus Upper = IDBRBU

• Unique PitID ⇨ 6-letter site code and timestamp (e.g. format: XXXXXX_yyyymmdd_hhmm, example: IDBRBU_20200116_1345)

Table 1. (Preliminary) Comprehensive Site Summary for 2020 and 2021 Time Series Campaign

State	Location	Site	PitID	Latitude	Longitude	Pit Count	Snow Class
CA	American River Basin	Caples Lake	CAAMCL	38.71029	-120.04186	7	3
CA	Mammoth Lakes	CUES	CAMLCP	37.64324	-119.02906	9	5
CA	Mammoth Lakes	Panorama Dome	CAMLPD	37.61964	-119.00029	6	6
CA	Sagehen Creek	Forest	CASHFO	39.42956	-120.24211	7	6
CA	Sagehen Creek	Open	CASHOP	39.43037	-120.23982	7	6
CA	Sagehen Creek	Tower 4	CASHT4	39.42216	-120.29898	6	3
CO	Cameron Pass	Cameron Peak	COCPCP	40.56381	-105.86761	16	6
CO	Cameron Pass	Joe Wright	COCPJW	40.52406	-105.89345	8	2
CO	Cameron Pass	Michigan River	COCPMR	40.51864	-105.89193	22	2
CO	East River	Aspen	COERAP	38.92529	-106.97109	9	6
CO	East River	Forest 12	COER12	38.92973	-106.97824	12	2
CO	East River	Forest 13	COER13	38.92943	-106.97777	9	6
CO	East River	Forest 14	COER14	38.92894	-106.97757	12	6
CO	East River	Gothic	COERGT	38.95925	-106.99053	9	6
CO	East River	Irwin Barn	COERIB	38.88812	-107.10796	13	2
CO	East River	Open 2	COERO2	38.92661	-106.97848	9	2
CO	East River	Open 4	COERO4	38.92627	-106.97907	12	2
CO	East River	Open 6	COERO6	38.92669	-106.97988	9	2
CO	East River	Trench 13	COERTR	38.92920	-106.97770	5	6
CO	East River	Upper	COERUP	38.93331	-106.98994	12	2
CO	Fraser Experimental Forest	JPL 1	COFEJ1	39.90556	-105.88282	35	6
CO	Fraser Experimental Forest	JPL 2	COFEJ2	39.90612	-105.88255	26	6
CO	Fraser Experimental Forest	SNB 1	COFEB1	39.90699	-105.87786	23	6
CO	Fraser Experimental Forest	SNB 2	COFEB2	39.90703	-105.87904	18	6
CO	Grand Mesa	County Line Open	COGMCO	39.03053	-108.03220	12	2
CO	Grand Mesa	County Line Tree	COGMCT	39.03223	-108.03438	10	2
CO	Grand Mesa	Mesa West Open	COGMWO	39.03399	-108.21390	10	2
CO	Grand Mesa	Mesa West Trees	COGMWT	39.03282	-108.21291	7	2
CO	Grand Mesa	Skyway Open	COGMSO	39.04511	-108.06209	21	2
CO	Grand Mesa	Skyway Tree	COGMST	39.04565	-108.06333	18	2
CO	Niwot Ridge	C1	CONWC1	40.03317	-105.54616	9	6
CO	Niwot Ridge	Forest Flat	CONWFF	40.03186	-105.54667	12	6
CO	Niwot Ridge	Forest North	CONWFN	40.03337	-105.55380	11	2
CO	Niwot Ridge	Forest South	CONWFS	40.04021	-105.55701	13	2
CO	Niwot Ridge	Open Flat	CONWOF	40.03579	-105.55205	15	6
CO	Niwot Ridge	Saddle	CONWSA	40.05497	-105.59065	7	1
CO	Senator Beck	Senator Beck	COSBSB	37.90705	-107.72626	5	1
CO	Senator Beck	Swamp Angel	COSBSA	37.90714	-107.71121	19	2
ID	Boise River Basin	Banner Open	IDBRBO	44.30456	-115.23601	11	6
ID	Boise River Basin	Banner Snotel	IDBRBS	44.30362	-115.23457	23	6
ID	Boise River Basin	Bogus Lower	IDBRBL	43.76434	-116.10660	17	6
ID	Boise River Basin	Bogus Lower Trees	IDBRBT	43.76057	-116.08979	13	6
ID	Boise River Basin	Bogus Upper	IDBRBU	43.75881	-116.09019	11	6
ID	Boise River Basin	LDP Open	IDBRLO	43.73707	-116.12179	19	6
ID	Boise River Basin	LDP Tree	IDBRLT	43.73634	-116.12053	17	6
ID	Boise River Basin	Mores Creek Summit	IDBRMC	43.94735	-115.67666	3	6
MT	Central Ag Research Center	SnowEx-1	MTCASX	47.05836	-109.95688	4	5
MT	Central Ag Research Center	Wheat	MTCAWH	47.05942	-109.95176	1	5
MT	Central Ag Research Center	Wx	MTCAWX	47.06062	-109.95693	4	5
NM	Jemez River	BA Flux Tower	NMJRBA	35.88859	-106.53184	8	5
NM	Jemez River	HQ Met Station	NMJRHQ	35.85791	-106.52137	8	5
UT	Little Cottonwood Canyon	Alta Collins	UTLCAC	40.57210	-111.62997	17	2
UT	Little Cottonwood Canyon	Atwater	UTLCAW	40.59125	-111.63759	20	5

Note - This table is a preliminary comprehensive site summary of the 2020 and 2021 Time Series campaigns. If a site was repeated (e.g. Cameron Pass, Michigan River) then the Pit Count column is a sum of the two years). This is preliminary because we are still adjusting and correcting some of the spatial data after confirming locations and sampling designs with site leads. The Snow Class column was extracted from the 300 m Snow Classification data set (Liston, 2021 and can be accessed here at NSIDC). See the previous notebook to characterize the Snow Classes. This table does not include about ~50 snow pits that were part of the 2021 TS campaign from the Fraser Experimental Forest because of the modified spatial sampling design, but will be included in the published data set, and the table will be updated to reflect those additional snow pits.

This table can be accessed as a geojson from Megan’s github gists

To use this as a geojson in your project:

1. Navigate to the link above

2. Check out the map of data (zoom in, zoom out, etc.)

3. Select the ‘Raw’ button from the top right corner

4. Copy/Paste the URL (it’s longer now)

5. Use the code block below to import

import geopandas as gpd
import requests
url = "https://gist.githubusercontent.com/meganmason/dde13c46a90875e364b1c25a31bff1d8/raw/d361e1a56eeb867bd89c87b4dc13ed431ffff6f6/SNEX_TS_SP_avg_prelim_Hackweek.geojson"
gdf = gpd.read_file(url)
gdf.head()

	State	Location	Site	PitID	Latitude	Longitude	Pit Count	Snow Class	geometry
0	CA	American River Basin	Caples Lake	CAAMCL	38.71029	-120.04186	7	3	POINT (-120.04186 38.71029)
1	CA	Mammoth Lakes	CUES	CAMLCP	37.64324	-119.02906	9	5	POINT (-119.02906 37.64324)
2	CA	Mammoth Lakes	Panorama Dome	CAMLPD	37.61964	-119.00029	6	6	POINT (-119.00029 37.61964)
3	CA	Sagehen Creek	Forest	CASHFO	39.42956	-120.24211	7	6	POINT (-120.24211 39.42956)
4	CA	Sagehen Creek	Open	CASHOP	39.43037	-120.23982	7	6	POINT (-120.23982 39.43037)

Where can I find data?

1. SnowEx data sets are stored and archived at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.

Table 2. Summary of Core Data Sets with DOI links for applicable data sets

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Core Data Sets	Parameters Available	Instruments	NSIDC DOI
Snow Pits	Depth, Density, Temp., LWC, Stratigraphy, Grain Size, Wetness, Hand Hardness, Qualitative Environment, SWE	Standard pit kit	SNEX17_SnowPits_GMIOP SNEX20_SnowPits_GMIOP SNEX20_TS_SP (in review) SNEX21_TS_SP (future pub.)
Depth Transects	Snow Depth - various sampling designs	MagnaProbe, Mesa2, Pit Ruler	SNEX17_SD SNEX20_SD SNEX20_TS_SD (future pub.) SNEX21_TS_SD (future pub.)
Interval Boards	New snow, SWE, density	Ruler and spring scale	SNEX20_TS_IB (in prep.) SNEX21_TS_IB (future pub.)

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Visit NSIDC’s SnowEx Overview page to see a full table of all available 2017, 2020, and 2021 products.

Figure 7. Representative snow pit data package for an individual pit visit.

2. SnowEx SQL Database (preview in next tutorial!)

Recap

• You know which measurements we have a LOT of and are consistent between multiple field campaigns

• You are aware of the basic sampling strategy for the two campaign types

• You have a few tools at your finger tips to access and learn more about the data

Share Your Thoughts

Group Mind Map Activity

1. Navigate to this Google Slides page to complete the Mind Map activity

2. Wait to be assigned a table number

3. Add your thoughts on data applications and research topics now that you know what measurements we have and where they occur.

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SnowEx Field Campaigns Overview

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SnowEx Database Preview