Incipient ferralization and weathering indices along a soil chronosequence in Taiwan

The low hilly topography of Green Island, a volcanic island off southeastern Taiwan, includes an altitudinal sequence of sub-horizontal benches. We examined eight profiles along this sequence, ranging from pale brown loamy coral sand on the lowest bench that fringes the coast at an elevation of about 10 m to deep, intensely red and acid clay on the highest bench at about 240 m. Chemical analyses, differential Fe extractions, thin sections, X-ray diffraction of the clay minerals and indices of pedochemical weathering and strain indicated that soil development progressed by weathering of primary and secondary phyllosilicates through argilluviation in the intermediate stages to the generation of increasing quantities of free Fe. The Fe accumulates as free sesquioxides, which crystallize with age. Taxonomically the soil types progress from sandy coral Arenosol, through Eutric Cambisol, Hypereutric Lixisol and Acrisol to incipient Ferralsol (Udipsamment → Eutrudept → Udalf → Udultisol → Udox in Soil Taxonomy). The profiles are interpreted as a chronosequence, although this is complicated by minor and upwardly diminishing contributions of reef coral to the mainly igneous parent materials. There are also variations in the andesitic-basaltic bedrock, and minor aeolian inputs in the higher and older soil types. Regional eustatic sea-level correlations, 14C dating of carbonates on the two lowest benches and estimates of local tectonic uplift indicate that the incipient Ferralsols on the upper bench might date from about 150 ka. The transition through argilluvial Acrisols to incipient sesquioxide-dominated Ferralsols appears, therefore, to develop within 100–200 ka on Green Island, which is faster than usual

Spectrally-invariant behavior of zenith radiance around cloud edges simulated by radiative transfer

In a previous paper, we discovered a surprising spectrally-invariant relationship in shortwave spectrometer observations taken by the Atmospheric Radiation Measurement (ARM) program. The relationship suggests that the shortwave spectrum near cloud edges can be determined by a linear combination of zenith radiance spectra of the cloudy and clear regions. Here, using radiative transfer simulations, we study the sensitivity of this relationship to the properties of aerosols and clouds, to the underlying surface type, and to the finite field-of-view (FOV) of the spectrometer. Overall, the relationship is mostly sensitive to cloud properties and has little sensitivity to other factors. At visible wavelengths, the relationship primarily depends on cloud optical depth regardless of cloud phase function, thermodynamic phase and drop size. At water-absorbing wavelengths, the slope of the relationship depends primarily on cloud optical depth; the intercept, by contrast, depends primarily on cloud absorbing and scattering properties, suggesting a new retrieval method for cloud drop effective radius. These results suggest that the spectrally-invariant relationship can be used to infer cloud properties near cloud edges even with insufficient or no knowledge about spectral surface albedo and aerosol properties

Studies in upper and lower atmosphere coupling

The theoretical and data-analytic work on upper and lower atmosphere coupling performed under a NASA Headquarters contract during the period April 1978 to March 1979 are summarized. As such, this report is primarily devoted to an overview of various studies published and to be published under this contract. Individual study reports are collected as exhibits. Work performed under the subject contract are in the following four areas of upper-lower atmosphere coupling: (1) Magnetosphere-ionosphere electrodynamic coupling in the aurora; (2) Troposphere-thermosphere coupling; (3) Ionosphere-neutral-atmosphere coupling; and (4) Planetary wave dynamics in the middle atmosphere