Roger Funk

Dr. Roger Funk


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2008 in Journal of Arid Environments
Verified
Journal Article
Closed access
CHC. Hoffmann
C. Hoffmann
RFRoger Funk
Roger Funk
RWR. Wieland
R. Wieland
YLY. Li
Y. Li
MSM. Sommer
M. Sommer

23 October 2003 in Earth Surface Processes and Landforms
Verified
Journal Article
Open access
PDF file
TZTed M. Zobeck
Ted M. Zobeck
GSGeert Sterk
Geert Sterk
RFRoger Funk
Roger Funk
JRJean Louis RAJOT
Jean Louis RAJOT
JSJohn Edward Stout
John Edward Stout
RPR. Scott Van Pelt
R. Scott Van Pelt
Accurate and reliable methods of measuring windblown sediment are needed to confirm, validate, and improve erosion models, assess the intensity of aeolian processes and related damage, determine the source of pollutants, and for other applications. This paper outlines important principles to consider in conducting field‐scale wind erosion studies and proposes strategies of field data collection for use in model validation and development. Detailed discussions include consideration of field characteristics, sediment sampling, and meteorological stations. The field shape used in field‐scale wind erosion research is generally a matter of preference and in many studies may not have practical significance. Maintaining a clear non‐erodible boundary is necessary to accurately determine erosion fetch distance. A field length of about 300 m may be needed in many situations to approach transport capacity for saltation flux in bare agricultural fields. Field surface conditions affect the wind profile and other processes such as sediment emission, transport, and deposition and soil erodibility. Knowledge of the temporal variation in surface conditions is necessary to understand aeolian processes. Temporal soil properties that impact aeolian processes include surface roughness, dry aggregate size distribution, dry aggregate stability, and crust characteristics. Use of a portable 2 tall anemometer tower should be considered to quantify variability of friction velocity and aerodynamic roughness caused by surface conditions in field‐scale studies. The types of samplers used for sampling aeolian sediment will vary depending upon the type of sediment to be measured. The Big Spring Number Eight (BSNE) and Modified Wilson and Cooke (MWAC) samplers appear to be the most popular for field studies of saltation. Suspension flux may be measured with commercially available instruments after modifications are made to ensure isokinetic conditions at high wind speeds. Meteorological measurements should include wind speed and direction, air temperature, solar radiation, relative humidity, rain amount, soil temperature and moisture. Careful consideration of the climatic, sediment, and soil surface characteristics observed in future field‐scale wind erosion studies will ensure maximum use of the data collected. Copyright © 2003 John Wiley & Sons, Ltd.

1 October 2008 in CATENA
Verified
Journal Article
Closed access
CHCarsten Hoffmann
Carsten Hoffmann
RFRoger Funk
Roger Funk
YLYong Li
Yong Li
MSMichael Sommer
Michael Sommer

21 August 2020 in Sustainability
Verified
Journal Article
Open access
PDF file
Jonathan SheppardJonathan Sheppard
Jonathan Sheppard
RRRafael Bohn Reckziegel
Rafael Bohn Reckziegel
LBLars Borrass
Lars Borrass
Paxie Wanangwa ChirwaPaxie Wanangwa Chirwa
Paxie Wanangwa Chirwa
CCClaudio J. Cuaranhua
Claudio J. Cuaranhua
HKHans-Peter Kahle
Hans-Peter Kahle
Agroforestry is often discussed as a strategy that can be used both for the adaptation to and the mitigation of climate change effects. The climate of southern Africa is predicted to be severely affected by such changes. With agriculture noted as the continent’s largest economic sector, issues such as food security and land degradation are in the forefront. In the light of such concerns we review the current literature to investigate if agroforestry systems (AFS) are a suitable response to the challenges besetting traditional agricultural caused by a changing climate. The benefits bestowed by AFS are multiple, offering ecosystem services, influence over crop production and positive impacts on rural livelihoods through provisioning and income generation. Nevertheless, knowledge gaps remain. We identify outstanding questions requiring further investigation such as the interplay between trees and crops and their combination, with a discussion of potential benefits. Furthermore, we identify deficiencies in the institutional and policy frameworks that underlie the adoption and stimulus of AFS in the southern African region. We uphold the concept that AFS remains an appropriate and sustainable response for an increased resilience against a changing climate in southern Africa for the benefit of livelihoods and multiple environmental values.

1 January 2015 in Environmental Development
Verified
Journal Article
Closed access
EMEleanor Milne
Eleanor Milne
SBSteven Banwart
Steven Banwart
ENElke Noellemeyer
Elke Noellemeyer
David J. AbsonDavid J. Abson
David J. Abson
CBCristiano Ballabio
Cristiano Ballabio
JZJufeng Zheng
Jufeng Zheng

20 October 2016 in Journal of Geophysical Research: Atmospheres
Verified
Journal Article
Open access
PDF file
ISI. Steinke
I. Steinke
RFRoger Funk
Roger Funk
JBJ. Busse
J. Busse
AIA. Iturri
A. Iturri
SKS. Kirchen
S. Kirchen
TLT. Leisner
T. Leisner
Soil dust particles emitted from agricultural areas contain considerable mass fractions of organic material. Also, soil dust particles may act as carriers for potentially ice‐active biological particles. In this work, we present ice nucleation experiments conducted in the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud chamber. We investigated the ice nucleation efficiency of four types of soil dust from different regions of the world. The results are expressed as ice nucleation active surface site (INAS) densities and presented for the immersion freezing and the deposition nucleation mode. For immersion freezing occurring at 254 K, samples from Argentina, China, and Germany show ice nucleation efficiencies which are by a factor of 10 higher than desert dusts. On average, the difference in ice nucleation efficiencies between agricultural and desert dusts becomes significantly smaller at temperatures below 247 K. In the deposition mode the soil dusts showed higher ice nucleation activity than Arizona Test Dust over a temperature range between 232 and 248 K and humidities RHice up to 125%. INAS densities varied between 109 and 1011 m−2 for these thermodynamic conditions. For one soil dust sample (Argentinian Soil), the effect of treatments with heat was investigated. Heat treatments (383 K) did not affect the ice nucleation efficiency observed at 249 K. This finding presumably excludes proteinaceous ice‐nucleating entities as the only source of the increased ice nucleation efficiency.