A New Formulation and Code to Compute Aerodynamic Roughness Length for Gridded Geometry—Tested on Lidar-Derived Snow Surfaces
Abstract
:1. Introduction
2. Methodology
2.1. Segmentation into Roughness Elements
2.2. Computing Areas and Heights
2.3. Smoothing of the Surface
3. Testing of the Formulation and Code on Seasonal Snow
4. Datasets and Preparation
4.1. Snow Surface Datasets
4.2. Data Preparation
5. Results
6. Discussion
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Abbreviations
AOI | is the area of interest h is the average vertical extent or effective obstacle height, measured in cm |
s | is the silhouette area of the average obstacle, measured in |
S | is the specific area or lot area, measured in |
is the (geometric) aerodynamic roughness length, measured in m |
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Step | Details | |
---|---|---|
Smoothing (Optional) | · Gaussian | |
· Small maxima suppression | ||
Segment roughness elements | via watershed algorithm on the inverted surface | |
For each obstacle | Determine lot area | from the extent of the watershed |
Determine silhouette area | restricting to the upwind component of obstacle | |
Determine height | restricting to the upwind component of obstacle | |
Compute | ||
Compute summary statistics | over all obstacles (for a single single wind direction) |
Dataset | Fresh Snow | Peak Accumulation | Ablation—Sun Cups |
---|---|---|---|
short name/code | FS-FC | PA-NS | SC-PH |
location | Fort Collins | Niwot Saddle | Poudre headwaters |
latitude, longitude | 40.6, −105.1 | 40.0547, −105.5890 | 40.4396, −105.7739 |
date acquired | 19 April 2021 | 20 May 2010 | 13 June 2017 |
resolution (m) | 0.001 | 1 | 0.05 |
Surface | Fresh Snow | - | Peak Accumulation | - | Ablation—Sun Cups | - |
---|---|---|---|---|---|---|
resolution (m) | 0.001 | 0.010 | 1 | 10 | 0.005 | 0.050 |
elements | 7366 | 195 | 21090 | 74 | 36259 | 380 |
mean () | 0.00054 | 0.0075 | 9.4 | 421 | 0.012 | 0.14 |
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Neville, R.A.; Shipman, P.D.; Fassnacht, S.R.; Sanow, J.E.; Pasquini, R.; Oprea, I. A New Formulation and Code to Compute Aerodynamic Roughness Length for Gridded Geometry—Tested on Lidar-Derived Snow Surfaces. Remote Sens. 2025, 17, 1984. https://doi.org/10.3390/rs17121984
Neville RA, Shipman PD, Fassnacht SR, Sanow JE, Pasquini R, Oprea I. A New Formulation and Code to Compute Aerodynamic Roughness Length for Gridded Geometry—Tested on Lidar-Derived Snow Surfaces. Remote Sensing. 2025; 17(12):1984. https://doi.org/10.3390/rs17121984
Chicago/Turabian StyleNeville, Rachel A., Patrick D. Shipman, Steven R. Fassnacht, Jessica E. Sanow, Ron Pasquini, and Iuliana Oprea. 2025. "A New Formulation and Code to Compute Aerodynamic Roughness Length for Gridded Geometry—Tested on Lidar-Derived Snow Surfaces" Remote Sensing 17, no. 12: 1984. https://doi.org/10.3390/rs17121984
APA StyleNeville, R. A., Shipman, P. D., Fassnacht, S. R., Sanow, J. E., Pasquini, R., & Oprea, I. (2025). A New Formulation and Code to Compute Aerodynamic Roughness Length for Gridded Geometry—Tested on Lidar-Derived Snow Surfaces. Remote Sensing, 17(12), 1984. https://doi.org/10.3390/rs17121984