How robust are in situ observations for validating satellite-derived albedo over the dark zone of the Greenland Ice Sheet?

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F17%3A10370086" target="_blank" >RIV/00216208:11310/17:10370086 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1002/2017GL073661" target="_blank" >http://dx.doi.org/10.1002/2017GL073661</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/2017GL073661" target="_blank" >10.1002/2017GL073661</a>

Jazyk výsledku

angličtina

Název v původním jazyce

How robust are in situ observations for validating satellite-derived albedo over the dark zone of the Greenland Ice Sheet?

Popis výsledku v původním jazyce

Calibration and validation of satellite-derived ice sheet albedo data require high-quality, in situ measurements commonly acquired by up and down facing pyranometers mounted on automated weather stations (AWS). However, direct comparison between ground and satellite-derived albedo can only be justified when the measured surface is homogeneous at the length-scale of both satellite pixel and in situ footprint. Here we use digital imagery acquired by an unmanned aerial vehicle to evaluate point-to-pixel albedo comparisons across the western, ablating margin of the Greenland Ice Sheet. Our results reveal that in situ measurements overestimate albedo by up to 0.10 at the end of the melt season because the ground footprints of AWS-mounted pyranometers are insufficient to capture the spatial heterogeneity of the ice surface as it progressively ablates and darkens. Statistical analysis of 21 AWS across the entire Greenland Ice Sheet reveals that almost half suffer from this bias, including some AWS located within the wet snow zone.

Název v anglickém jazyce

How robust are in situ observations for validating satellite-derived albedo over the dark zone of the Greenland Ice Sheet?

Popis výsledku anglicky

Calibration and validation of satellite-derived ice sheet albedo data require high-quality, in situ measurements commonly acquired by up and down facing pyranometers mounted on automated weather stations (AWS). However, direct comparison between ground and satellite-derived albedo can only be justified when the measured surface is homogeneous at the length-scale of both satellite pixel and in situ footprint. Here we use digital imagery acquired by an unmanned aerial vehicle to evaluate point-to-pixel albedo comparisons across the western, ablating margin of the Greenland Ice Sheet. Our results reveal that in situ measurements overestimate albedo by up to 0.10 at the end of the melt season because the ground footprints of AWS-mounted pyranometers are insufficient to capture the spatial heterogeneity of the ice surface as it progressively ablates and darkens. Statistical analysis of 21 AWS across the entire Greenland Ice Sheet reveals that almost half suffer from this bias, including some AWS located within the wet snow zone.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10508 - Physical geography

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geophysical Research Letters

ISSN

0094-8276

e-ISSN

—

Svazek periodika

44

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

6218-6225

Kód UT WoS článku

000405854200040

EID výsledku v databázi Scopus

2-s2.0-85021300223