Hi, I'm an error. x

Nocturnal Near-Surface Temperature, but not Flow Dynamics, can be Predicted by Microtopography in a Mid-Range Mountain Valley


Authors: Lena Pfister
Owners: CTEMPs OSU-UNR
Resource type:Composite Resource
Created:Dec 29, 2017 at 11:02 p.m.
Last updated: Apr 09, 2018 at 8:47 p.m. by CTEMPs OSU-UNR

Abstract

We investigate nocturnal flow dynamics and temperature behaviour near the surface of a 170-m long gentle slope in a mid-range mountain valley. In contrast to many existing studies focusing on locations with significant topographic variations, gentle slopes cover a greater spatial extent of the Earth’s surface. Air temperatures were measured using the high-resolution distributed-temperature-sensing method within a two-dimensional fibre-optic array in the lowest metre above the surface. The main objectives are to characterize the spatio-temporal patterns in the near-surface temperature and flow dynamics, and quantify their responses to the microtopography and land cover. For the duration of the experiment, including even clear-sky nights with weak winds and strong radiative forcing, the classical cold-air drainage predicted by theory could not be detected. In contrast, we show that the airflow for the two dominant flow modes originates non-locally. The most abundant flow mode is characterized by vertically-decoupled layers featuring a near-surface flow perpendicular to the slope and strong stable stratification, which contradicts the expectation of a gravity-driven downslope flow of locally produced cold air. Differences in microtopography and land cover clearly affect spatio-temporal temperature perturbations. The second most abundant flow mode is characterized by strong mixing, leading to vertical coupling with airflow directed down the local slope. Here variations of microtopography and land cover lead to negligible near-surface temperature perturbations. We conclude that spatio-temporal temperature perturbations, but not flow dynamics, can be predicted by microtopography, which complicates the prediction of advective-heat components and the existence and dynamics of cold-air pools in gently sloped terrain in the absence of observations.

Raw project data is available by contacting ctemps@unr.edu

Subject Keywords

distributed temperature sensing,flow dynamics,stable boundary layer,nocturnal near-surface temperature,CTEMPs,DTS,fibre optics

How to cite

Pfister, L. (2018). Nocturnal Near-Surface Temperature, but not Flow Dynamics, can be Predicted by Microtopography in a Mid-Range Mountain Valley, HydroShare, http://www.hydroshare.org/resource/596a04f086b84284a83134c658fc8942

This resource is shared under the Creative Commons Attribution CC BY.

 http://creativecommons.org/licenses/by/4.0/
CC-BY

Sharing status:

  • Public Resource  Public
  • Sharable Resource  Shareable

Content

Download All Content as Zipped BagIt Archive
Learn more about the Bagit archive format

Authors

The people or organizations that created the intellectual content of the resource.

Name Organization Address Phone Author Identifiers
Lena Pfister

Ratings

Be the first one to  +1 this.  (You need to be logged in to rate this.)

Comments

There are currently no comments

New Comment

required