Techniques to measure the dry aeolian deposition of dust in arid and semi‐arid landscapes: a comparative study in West Niger

Abstract

Seven techniques designed to measure the dry aeolian deposition of dust on a desert surface were tested during field experiments in Niger, central-west Africa. Deposition fluxes were measured during eight periods of 3-4 days each. Experimental techniques tested were the MDCO (marble dust collector) method, the Frisbee method, the glass plate method (optical analysis of dust deposited on glass surfaces using particle imaging software), the soil surface method (deposition on a simulated desert floor) and the CAPYR (capteur pyramidal) method. Theoretical techniques tested were the inferential method and the combination method (gradient method extended with a deposition term for coarse dust particles). The results obtained by the MDCO, Frisbee, inferential and combination methods could be directly compared by converting the data to identical standard conditions (deposition on a water surface producing no resuspension). The results obtained by the other methods (glass plate, soil surface, CAPYR) were compared relatively. The study shows that the crude (unconverted) deposition fluxes of the five experimental techniques were similar, while the crude deposition fluxes calculated by the two theoretical techniques were substantially higher, of the order of four to five times as high as for the experimental techniques. Recalculation of the data to identical environmental conditions (the standard water surface) resulted in nearly identical deposition fluxes for the MDCO, Frisbee, inferential and combination techniques, although the latter two still had slightly higher values (but the differences remained small). The measurements illustrate the need to include a grain shape factor in theoretical dust deposition models. Without such a factor, theoretical models overestimate the deposition. The paper also discusses the advantages and disadvantages of the techniques tested.

Deposition Rate and Chemical Composition of the Aeolian Dust from a Bare Saline Playa, Ebinur Lake, Xinjiang, China

“…It should be noted that the results of measuring the deposition of dust and salts depend on the sampling method (Goossens and Rajot 2008). A simple polyethylene cylinder collector used in our study can give somewhat underestimated results in comparison with a marble dust collector or a Frisbee-type collector with special trapping mechanisms as the reentrainment of dust and salt particles is not excluded.…”

Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

“…Although the time periods of precipitation or non-precipitation are readily separable using a precipitation sensor, reliable sampling of the amount and size distribution for dry deposition are difficult because of variable collection efficiency depending on the particle size, wind speed, and the collector shape (Goossens, 2005(Goossens, , 2007. Evaluations and improvements of various dry deposition collectors have been reported, but no perfect method of dry deposition exists (Vallack and Chadwick, 1992;Sow et al, 2006;Goossens and Rajot, 2008).…”

Influence of dust accumulation on building roof thermal performance and radiant heat gain in hot-dry climates

“…In the field, dust accumulation can be measured by various methods. In West Niger, Goossens and Rajot [34] used and tested seven different theoretical and experimental techniques. ElDesoky et al [16] and Modaihsh and Mahjou [17] collected the dust by using a marble dust collector.…”