On the structuralist view of inflation in some Latin American countries: A reassessment

Comparing inflation rates internationally, one finds a number of Latin American countries in the lead. Therefore, when investigating inflation in LDCs, it has become common practice to refer to these countries as prime examples. Mainly two theories have been put forward to explain Latin American inflation: the monetarist and structuralist hypotheses. While in the monetarist theory aggregate excess demand resulting from an excess supply of money is regarded as the only cause of inflation, the structuralist theory ascribes inflation also to the composition of demand for products and services accompanied by inflexibilities in the productive structure. The purpose of this paper is to give further empirical evidence for the structuralist view of inflation in six selected Latin American countries: Bolivia, Brazil, Chile, Colombia, Ecuador and Peru. They have all been highly prone to inflation in the past. First, we outline the theoretical background of our investigation. Subsequently, empirical tests of the hypotheses are provided. Finally, we draw some conclusions from our study and relate the findings to the discussion of the harmful effects of export instability in LDCs.

The Impact of rising international interest rates on developing countries: The South Korean experience

This paper evaluates the impact of rising international interest rates on the South Korean economy during the seventies with the help of an econometric macro model. The results show that there was an induced reduction of investment and GDP, yet inflationary pressures were somewhat mitigated by a lowering of capital inflows.

Quantifying the bias of radiative heating rates in numerical weather prediction models for shallow cumulus clouds

The interaction between radiation and clouds represents a source of uncertainty in numerical weather prediction (NWP) due to both intrinsic problems of one-dimensional radiation schemes and poor representation of clouds. The underlying question addressed in this study is how large the NWP radiative bias is for shallow cumulus clouds and how it scales with various input parameters of radiation schemes, such as solar zenith angle, surface albedo, cloud cover and liquid water path. A set of radiative transfer calculations was carried out for a realistically evolving shallow cumulus cloud field stemming from a large-eddy simulation (LES). The benchmark experiments were performed on the highly resolved LES cloud scenes (25 m grid spacing) using a three-dimensional Monte Carlo radiation model. An absence of middle and high clouds is assumed above the shallow cumulus cloud layer. In order to imitate the poor representation of shallow cumulus in NWP models, cloud optical properties were horizontally averaged over the cloudy part of the boxes with dimensions comparable to NWP horizontal grid spacing (several kilometers), and the common delta-Eddington two-stream method with maximum-random overlap assumption for partial cloudiness was applied (denoted as the "1-D" experiment). The bias of the 1-D experiment relative to the benchmark was investigated in the solar and thermal parts of the spectrum, examining the vertical profile of heating rate within the cloud layer and the net surface flux. It is found that, during daytime and nighttime, the destabilization of the cloud layer in the benchmark experiment is artificially enhanced by an overestimation of the cooling at cloud top and an overestimation of the warming at cloud bottom in the 1-D experiment (a bias of about - 15 K d(-1) is observed locally for stratocumulus scenarios). This destabilization, driven by the thermal radiation, is maximized during nighttime, since during daytime the solar radiation has a stabilizing tendency. The daytime bias at the surface is governed by the solar fluxes, where the 1-D solar net flux overestimates (underestimates) the corresponding benchmark at low (high) Sun. The overestimation at low Sun (bias up to 80 % over land and ocean) is largest at intermediate cloud cover, while the underestimation at high Sun (bias up to -40 % over land and ocean) peaks at larger cloud cover (80 % and beyond). At nighttime, the 1-D experiment overestimates the amount of benchmark surface cooling with the maximal bias of about 50 % peaked at intermediate cloud cover. Moreover, an additional experiment was carried out by running the Monte Carlo radiation model in the independent column mode on cloud scenes preserving their LES structure (denoted as the "ICA" experiment). The ICA is clearly more accurate than the 1-D experiment (with respect to the same benchmark). This highlights the importance of an improved representation of clouds even at the resolution of today's regional (limited-area) numerical models, which needs to be considered if NWP radiative biases are to be efficiently reduced. All in all, this paper provides a systematic documentation of NWP radiative biases, which is a necessary first step towards an improved treatment of radiation-cloud interaction in atmospheric models

The incorporation of the Tripleclouds concept into the delta-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds

The treatment of unresolved cloud-radiation interactions in weather and climate models has considerably improved over the recent years, compared to conventional plane-parallel radiation schemes, which previously persisted in these models for multiple decades. One such improvement is the state-of-the-art Tripleclouds radiative solver, which has one cloud-free and two cloudy regions in each vertical model layer and is thereby capable of representing cloud horizontal inhomogeneity. Inspired by the Tripleclouds concept, primarily introduced by Shonk and Hogan (2008), we incorporated a second cloudy region into the widely employed delta-Eddington two-stream method with the maximum-random overlap assumption for partial cloudiness. The inclusion of another cloudy region in the two-stream framework required an extension of vertical overlap rules. While retaining the maximum-random overlap for the entire layer cloudiness, we additionally assumed the maximum overlap of optically thicker cloudy regions in pairs of adjacent layers. This extended overlap formulation implicitly places the optically thicker region towards the interior of the cloud, which is in agreement with the core-shell model for convective clouds. The method was initially applied on a shallow cumulus cloud field, evaluated against a three-dimensional benchmark radiation computation. Different approaches were used to generate a pair of cloud condensates characterizing the two cloudy regions, testing various condensate distribution assumptions along with global cloud variability estimate. Regardless of the exact condensate setup, the radiative bias in the vast majority of Tripleclouds configurations was considerably reduced compared to the conventional plane-parallel calcula- tion. Whereas previous studies employing the Tripleclouds concept focused on researching the top-of-the-atmosphere radiation budget, the present work applies Tripleclouds to atmospheric heating rate and net surface flux. The Tripleclouds scheme was implemented in the comprehensive libRadtran radiative transfer package and can be utilized to further address key scientific issues related to unresolved cloud-radiation interplay in coarse-resolution atmospheric models

3-D radiative transfer in large-eddy simulations - experiences coupling the TenStream solver to the UCLA-LES

The recently developed 3-D TenStream radiative transfer solver was integrated into the University of California, Los Angeles large-eddy simulation (UCLA-LES) cloud-resolving model. This work documents the overall performance of the TenStream solver as well as the technical challenges of migrating from 1-D schemes to 3-D schemes. In particular the employed Monte Carlo spectral integration needed to be reexamined in conjunction with 3-D radiative transfer. Despite the fact that the spectral sampling has to be performed uniformly over the whole domain, we find that the Monte Carlo spectral integration remains valid. To understand the performance characteristics of the coupled TenStream solver, we conducted weak as well as strong-scaling experiments. In this context, we investigate two matrix pre-conditioner: geometric algebraic multigrid preconditioning (GAMG) and block Jacobi incomplete LU (ILU) factorization and find that algebraic multigrid preconditioning performs well for complex scenes and highly parallelized simulations. The TenStream solver is tested for up to 4096 cores and shows a parallel scaling efficiency of 80-90% on various supercomputers. Compared to the widely employed 1-D delta-Eddington two-stream solver, the computational costs for the radiative transfer solver alone increases by a factor of 5-10

Chemical and Isotopic Evaluation of Sulfur Sources and Cycling in the Pecos River, New Mexico, USA

The use of stable isotopes in studies of watershed biogeochemical processes has increased greatly throughout the last several decades. Much of the sulfur cycling research has addressed the influence of changes in atmospheric acid deposition on sulfur dynamics in temperate ecosystems. Little is known about sulfur cycling in dryland ecosystems such as those in the American Southwest. To identify the sources and assess the cycling of sulfur in dryland ecosystems, chemical and isotopic compositions of water were measured on samples collected from the Pecos River (New Mexico, USA) during a reconnaissance survey in spring 2010. Based on the chemical and isotopic results, the Pecos River is readily divided into an upper basin of 6,000 km2 above Santa Rosa Lake and a lower basin of 44,000 km2 above Red Bluff Reservoir in western Texas. The upper basin contains river water with low concentrations of chloride (3 mg/L) and sulfate (13 mg/L), low values of δD (− 87‰) and δ18O (− 12.3‰), and low δ34S (− 4.3‰) and δ18O values (2.6‰) of dissolved sulfate (δ34SSO4 and δ18OSO4). Three different sources contributing to the pool of dissolved sulfate are identified, namely the oxidation of sulfide minerals, the soil processing of atmospheric sulfate, and the dissolution of ancient evaporites. The relative contributions of the three different sulfate sources change from reach to reach. Sulfate from evaporite dissolution primarily of Permian age dominates in the lower reaches while sulfate from sulfide oxidation dominates in the upper part of the Pecos River. Despite significant lithologic variations across the lower basin, δ34SSO4 values of river water are quite constant, with an average value of 11.8‰. In contrast, a 5‰ decrease was observed in δ18OSO4 values of river water between upstream and downstream reaches of the lower Pecos River, indicating that 63% of the dissolved sulfate had been recycled. Surprisingly, most of the sulfur cycling observed occurs in two small irrigation districts (the Fort Sumner Irrigation District and the Carlsbad Irrigation District), whereas there is only a minimal decrease (0.7‰) in δ18OSO4 in the largest irrigation district (the Pecos Valley Artesian Conservancy District). This study implies that the influence of land use activities on sulfur cycling may be more profound than previously thought

Ice crystal characterization in cirrus clouds III: retrieval of ice crystal shape and roughness from observations of halo displays

In this study, which is the third part of the HaloCam series after , we present a novel technique to retrieve quantitative information about ice crystal optical and microphysical properties using ground-based imaging observations of halo displays. Comparing HaloCam's calibrated RGB images of 22 and 46 & LCIRC;halo observations against a lookup table of simulated radiances, this technique allows the retrieval of the sizes and shapes of randomly oriented crystals as well as the fraction of smooth and rough ice crystals for cirrus clouds. We analyzed 4400 HaloCam images between September 2015 and November 2016 showing a visible 22 & LCIRC;halo. The optical properties of hexagonal 8-element aggregates of columns with a mean ice crystal effective radius of about 20 mu m and a mixture of 37 % smooth and 63 % rough crystals on average best match the HaloCam observations. Implemented on different sites, HaloCam in combination with the machine-learning-based halo detection algorithm HaloForest can provide a consistent dataset for climatological studies of ice crystal properties representing typical cirrus clouds. Representative ice crystal optical properties are required for remote sensing of cirrus clouds as well as climate modeling. Since ground-based passive imaging observations provide information about the forward scattering part of the ice crystal optical properties, the results of this work ideally complement the results of satellite-based and airborne studies

Accurate 3-D radiative transfer simulation of spectral solar irradiance during the total solar eclipse of 21 August 2017

We calculate the variation of spectral solar irradiance in the umbral shadow of the total solar eclipse of 21 August 2017 and compare it to observations. Starting from the Sun's and Moon's positions, we derive a realistic profile of the lunar shadow at the top of the atmosphere, including the effect of solar limb darkening. Subsequently, the Monte Carlo model MYSTIC (Monte Carlo code for the phYSically correct Tracing of photons In Cloudy atmospheres) is used to simulate the transfer of solar radiation through the Earth's atmosphere. Among the effects taken into account are the atmospheric state (pressure, temperature), concentrations of major gas constituents and the curvature of the Earth, as well as the reflectance and elevation of the surrounding area. We apply the model to the total solar eclipse on 21 August 2017 at a position located in Oregon, USA, where irradiance observations were performed for wavelengths between 306 and 1020 nm. The influence of the surface reflectance, the ozone profile, the mountains surrounding the observer and aerosol is investigated. An increased sensitivity during totality is found for the reflectance, aerosol and topography, compared to non-eclipse conditions. During the eclipse, the irradiance at the surface not only depends on the total ozone column (TOC) but also on the vertical ozone distribution, which in general complicates derivations of the TOC from spectral surface irradiance. The findings are related to an analysis of the prevailing photon path and its difference compared to non-eclipse conditions. Using the most realistic estimate for each parameter, the model is compared to the irradiance observations. During totality, the relative difference between model and observations is less than 10% in the spectral range from 400 to 1020 nm. Slightly larger deviations occur in the ultraviolet range below 400 and at 665 nm

Dependence of aptamer activity on opposed terminal extensions : improvement of light-regulation efficiency

Aptamers that can be regulated with light allow precise control of protein activity in space and time and hence of biological function in general. In a previous study, we showed that the activity of the thrombin-binding aptamer HD1 can be turned off by irradiation using a light activatable "caged" intramolecular antisense-domain. However, the activity of the presented aptamer in its ON state was only mediocre. Here we studied the nature of this loss in activity in detail and found that switching from 5'- to 3'-extensions affords aptamers that are even more potent than the unmodified HD1. In particular we arrived at derivatives that are now more active than the aptamer NU172 that is currently in phase 2 clinical trials as an anticoagulant. As a result, we present light-regulatable aptamers with a superior activity in their ON state and an almost digital ON/OFF behavior upon irradiation

A fast method for the retrieval of integrated longwave and shortwave top-of-atmosphere upwelling irradiances from MSG/SEVIRI (RRUMS)

A new Rapid Retrieval of Upwelling irradiances from MSG/SEVIRI (RRUMS) is presented. It has been developed to observe the top-of-atmosphere irradiances of small scale and rapidly changing features that are not sufficiently resolved by specific Earth radiation budget sensors. Our retrieval takes advantage of the spatial and temporal resolution of MSG/SEVIRI and provides outgoing longwave and reflected shortwave radiation only by means of a combination of SEVIRI channels. The longwave retrieval is based on a simple linear combination of brightness temperatures from the SEVIRI infrared channels. The shortwave retrieval is based on a neural network that requires as input the visible and near-infrared SEVIRI channels