Spectral albedo and summer ground temperature of herbaceous and shrub tundra vegetation at Bylot Island, Canadian High-Arctic

These data are in support of a preprint: Comparing spectral albedo and NDVI of herbaceous and shrub tundra vegetation at Bylot Island, Canadian High-Arctic Florent Domine, Maria-Belke-Brea, Ghislain Picard, Laurent Arnaud, and Esther Lévesque To be submitted in 2023. The spectral albedo of several vegetation assemblages on Bylot Island and in Mala River valley on nearby Baffin Island were recorded between 10 and 18 July 2015. The spectral range covered was 346 to 2400 nm. Surfaces were classified according to the main vegetation types. Classes used are graminoids, moss, Salix arctica, soil, and Salix richardsonii. S. richardsonii is the only truly erect species on Bylot Island. Transmission spectra of radiation through the S. richardsonii canopy were also recorded. S. richardsonii spectra were different depending on the location where they were measured and we present spectra for sites in active parts of an alluvial fan (Salix-G2), an inactive part of an alluvial fan (Salix-D1) and in a mesic area on Mala River Valley (Salix-M). We also present typical relative solar irradiance spectra recorded at Bylot Island during the campaign, under clear and overcast conditions. In conjunction with spectral albedo data, these irradiance spectra allow the calculation of the broadband (BB) albedo of the vegetation types and to compare BB albedo values under identical irradiance conditions. 83 spectra were recorded: 39 for S. richardsonii and 44 for low vegetation and soil. 17 transmission spectra under S. richardsonii were recorded. We present here only averages for each vegetation type. We also present averages for all low vegetation types and for all S. richardsonii spectra, to allow the calculation of the radiative impact of erect shrubs at Bylot Island. We also present soil temperature data at 15 cm depth for the spots GRASS (mostly Salix Arctica), TUNDRA (Mostly moss), SALIX-D1 (Salix richardsonii) and SALIX-F (Salix richardsonii). SALIX-F is similar to SALIX-G2. The data are during summer 2020. The locations of the various spots investigated are: Spot name Latitude Longitude Vegetation types found TUNDRA 73.150° -80.004° Humid and moist polygons with low vegetation dominated by mosses, graminoids, S. arctica and S. herbacea. PLAINE 73.167° -79.915° Low vegetation and bare soil patches caused by cryoturbation (mudboils) with mosses, graminoids and S. arctica. GRASS 73.158° -79.907° Low vegetation between patches of S. richardsonii dominated by S. arctica, with litter, mosses, graminoids and occasional bare soil. SALIX-D1 73.158° -79.907° Scattered patches of S. richardsonii <35 cm tall. Understory is mosses, graminoids, litter, S. arctica and bare soil. SALIX-M 73.006° -80.685° Mesic area with patches of S. richardsonii 35 to 40 cm tall. Understory includes moss, graminoids and litter. Between patches: herb tundra with graminoids and mosses. The area is not within an alluvial fan. SALIX-G2 73.168° -79.812° Extended area in an alluvial fan with S. richardsonii >40 cm. Understory includes litter, mosses, graminoids, bare soil, S. arctica and S. reticulata. SALIX-F 73.182° -79.745° Similar to SALIX-G2. Ground temperature is monitored there. No spectral data were recorded at that site.本数据集支撑以下预印本：《加拿大高北极地区拜洛特岛草本与灌丛苔原植被的光谱反照率（spectral albedo）与归一化差分植被指数（Normalized Difference Vegetation Index, NDVI）对比》，作者为Florent Domine、Maria-Belke-Brea、Ghislain Picard、Laurent Arnaud及Esther Lévesque，计划于2023年提交。 2015年7月10日至18日，研究团队在拜洛特岛及邻近巴芬岛马拉河谷的多个植被群落中开展了光谱反照率测量，光谱覆盖范围为346~2400 nm。研究按主要植被类型对地表进行分类，分类类别包括禾本科植物、苔藓、北极柳（*Salix arctica*）、土壤以及理查森柳（*Salix richardsonii*）——其中理查森柳是拜洛特岛上唯一真正直立的灌丛物种。 研究团队同时记录了透过理查森柳冠层的辐射透射光谱。观测发现，理查森柳的光谱特征会因测量点位不同而存在差异，本次研究提供了冲积扇活跃区域（Salix-G2点位）、冲积扇非活跃区域（Salix-D1点位）以及马拉河谷中生区域（Salix-M点位）的理查森柳光谱数据。此外还提供了本次科考期间在拜洛特岛晴朗与阴天条件下记录的典型太阳相对辐照度光谱。结合光谱反照率数据与这些辐照度光谱，可计算不同植被类型的宽带反照率（broadband albedo, BB），并在相同辐照度条件下对比各类植被的宽带反照率数值。 本次共记录83条光谱数据：其中理查森柳光谱39条，低矮植被与土壤光谱44条；另记录了17条理查森柳冠层的透射光谱。本文仅提供各类植被类型的平均光谱数据，同时也提供了所有低矮植被类型的平均光谱以及所有理查森柳光谱的平均数据，以便开展拜洛特岛直立灌丛的辐射影响相关计算。 研究团队还提供了四个测点的15cm深度土壤温度数据，分别为GRASS（以北极柳为主）、TUNDRA（以苔藓为主）、SALIX-D1以及SALIX-F，其中SALIX-F与SALIX-G2点位特征相似，相关温度数据采集于2020年夏季。 本次研究涉及的各测点详细信息如下： 1. TUNDRA：纬度73.150°，经度-80.004°，地表为湿润与潮湿多边形地貌，低矮植被以苔藓、禾本科植物、北极柳以及草本柳（*S. herbacea*）为主。 2. PLAINE：纬度73.167°，经度-79.915°，存在因冻融扰动（泥火山）形成的低矮植被与裸土斑块，植被包括苔藓、禾本科植物与北极柳。 3. GRASS：纬度73.158°，经度-79.907°，位于理查森柳斑块之间的低矮植被群落，优势种为北极柳，伴生枯落物、苔藓、禾本科植物以及零星裸土。 4. SALIX-D1：纬度73.158°，经度-79.907°，分布高度低于35 cm的零散理查森柳斑块，下层植被包括苔藓、禾本科植物、枯落物、北极柳以及裸土。 5. SALIX-M：纬度73.006°，经度-80.685°，为中生区域，分布高度35~40 cm的理查森柳斑块，下层植被包含苔藓、禾本科植物与枯落物；斑块间为以禾本科植物与苔藓为主的草本苔原，该区域不属于冲积扇范围。 6. SALIX-G2：纬度73.168°，经度-79.812°，为冲积扇中的连片区域，分布高度超过40 cm的理查森柳，下层植被包括枯落物、苔藓、禾本科植物、裸土、北极柳以及网状柳（*S. reticulata*）。 7. SALIX-F：纬度73.182°，经度-79.745°，与SALIX-G2点位特征相似，设有地面温度监测装置，但未在此处采集光谱数据。