Drone measurements of surface-based winter temperature inversions in the High Arctic at Eureka
<p>The absence of sunlight during the winter in the High Arctic results in a strong surface-based atmospheric temperature inversion, especially during clear skies and light surface wind conditions. The inversion suppresses turbulent heat transfer between the ground and the boundary layer. As a...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-11-01
|
| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/14/7123/2021/amt-14-7123-2021.pdf |
| Summary: | <p>The absence of sunlight during the winter in the High Arctic results in a strong surface-based atmospheric temperature inversion, especially during clear skies and light surface wind conditions. The inversion suppresses turbulent heat transfer between the ground and the boundary layer. As a result, the difference between the surface air temperature, measured at a height of 2 <span class="inline-formula">m</span>, and the ground skin temperature can exceed several degrees Celsius. Such inversions occur very frequently in polar regions, are of interest to understand the mechanisms responsible for surface–atmosphere heat, mass, and momentum exchanges, and are critical for satellite validation studies.</p>
<p>In this paper we present the results of operations of two commercial remotely piloted aircraft systems, or drones, at the Polar Environment Atmospheric Research Laboratory, Eureka, Nunavut, Canada, at 80<span class="inline-formula"><sup>∘</sup> N</span> latitude. The drones are the Matrice 100 and Matrice 210 RTK quadcopters manufactured by DJI and were flown over Eureka during the February–March field campaigns in 2017 and 2020. They were equipped with a temperature measurement system built on a Raspberry Pi single-board computer, three platinum-wire temperature sensors, a Global Navigation Satellite System receiver, and a barometric altimeter.</p>
<p>We demonstrate that the drones can be effectively used in the extremely challenging High Arctic conditions to measure vertical temperature profiles up to 75 <span class="inline-formula">m</span> above the ground and sea ice surface at ambient temperatures down to <span class="inline-formula">−</span>46 <span class="inline-formula"><sup>∘</sup>C</span>. Our results indicate that the inversion lapse rates within the 0–10 <span class="inline-formula">m</span> altitude range above the ground can reach values of <span class="inline-formula">∼</span> 10–30 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi><mspace width="0.25em" linebreak="nobreak"/><mo>(</mo><mn mathvariant="normal">100</mn><mspace width="0.125em" linebreak="nobreak"/><mi mathvariant="normal">m</mi><msup><mo>)</mo><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="3f7e8df361f9792f4e8e54e96728fb07"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-14-7123-2021-ie00001.svg" width="63pt" height="15pt" src="amt-14-7123-2021-ie00001.png"/></svg:svg></span></span> (<span class="inline-formula">∼</span> 100–300 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><msup><mi/><mo>∘</mo></msup><mi mathvariant="normal">C</mi><mspace linebreak="nobreak" width="0.125em"/><msup><mi mathvariant="normal">km</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="40pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="5f9a5e3d9fe6585b18e5ebb93c674d0f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-14-7123-2021-ie00002.svg" width="40pt" height="13pt" src="amt-14-7123-2021-ie00002.png"/></svg:svg></span></span>). The results are in good agreement with the coincident surface air temperatures measured at 2, 6, and 10 <span class="inline-formula">m</span> levels at the National Oceanic and Atmospheric Administration flux tower at the Polar Environment Atmospheric Research Laboratory. Above 10 <span class="inline-formula">m</span> more gradual inversion with order-of-magnitude smaller lapse rates is recorded by the drone. This inversion lapse rate agrees well with the results obtained from the radiosonde temperature measurements. Above the sea ice drone temperature profiles are found to have an isothermal layer above a surface-based layer of instability, which is attributed to the heat flux through the sea ice. With the drones we were able to evaluate the influence of local topography on the surface-based inversion structure above the ground and to measure extremely cold temperatures of air that can pool in topographic depressions. The unique technical challenges of conducting drone campaigns in the winter High Arctic are highlighted in the paper.</p> |
|---|---|
| ISSN: | 1867-1381 1867-8548 |