A novel non-gradient model was proposed for estimating CO₂ fluxes from single-level time-series record of near-surface CO₂ concentration. The model formulation is based on a diffusion equation describing the one-dimensional turbulent transport of CO₂ in the atmospheric boundary layer. A new parameterization of eddy-diffusivity is used to reduce the sensitivity of the modeled CO₂ fluxes to the uncertainties of the model inputs and parameters. The newly formulated non-gradient model facilitates remote sensing applications as the new model does not use bulk gradient of CO₂ concentration, wind speed, surface roughness, and vegetation specific data. Tests of the new model using remote sensing data demonstrate its usefulness and potential.

The recent spectral evidence supporting the hypothesis that Recurring Slope Lineae (RSL) on Mars are modern-day active flows of liquid water (Ojha et al., 2015), has called into question both the formation mechanism for the flows and the factors that affect their activity. We utilize nadir observations from the Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor to test our hypothesis that the RSL serve as a sink or source for atmospheric water vapor. This involves a retrieval of the column atmospheric water vapor abundance from TES observations of RSL sites---through use of a radiative transfer model. The presented retrievals use an emission and absorption only model. We will also discuss the development of a radiative transfer model including the effects of multiple scattering. We present retrievals of the column water vapor abundance over RSL sites in the southern and northern midlatitudes as well as the equatorial region. Specifically, we look for enhancements in the column water vapor abundance over RSL sites relative to the surrounding regions. This also involves dividing out the dominant seasonal trends in the water vapor abundance (enhancement in northern summer) to look for these small-scale enhancements. Our study provides constraints on the extent of interaction between the RSL and atmospheric water vapor through evaporation.

An important factor that determines the optical property of mineral dust is its components because of varied reflective indexes for different chemical species and different ways these components aggregated. In addition, the component is important to dust transport and interaction of dust with microphysical processes. However, currently mineral particles are uniformly assigned in a regional model and only in a few articles they were treated as multi-component ones but limited in global model which typically has a low spatial resolution. Here we incorporated several size-resolved mineral components (clay-sized and silt-sized) based on situ observations from literatures into a fully coupled WRF-Chem-DuMo (3.7.1) for Central Asia. The mineralogy fraction differs among varied sub-regions in Central Asia through being linked directly with the parent soil. However, Iron oxides were added uniformly as impurities at the expense of other components. Using this model, we consider an internally mixed mineralogy to simulate the daily mean net radiative forcing (short and long wavelength) by dust at both top of the atmosphere (TOA) and surface in Central Asia. In the simulation, we also employed a series set of different surface albedo and regional land cover and land use (LCLU) states to reflect effects of both regional climate change and/or human activity under various meteorology conditions. The modeled aerosol optical depth (AOD) was compared with available satellite retrievals and AERONET measurement in this region.

Tweek atmospherics generated by lightning discharges can be utilized to monitor the night-time upper atmosphere. This paper aims to estimate the night-time upper atmospheric very low frequency reflection heights (h), equivalent electron densities (ne) at the tweek atmospherics reflection heights and the tweek propagation distance (d). The D?region reflection height estimated 74.8 km before sunset, and rose to 94.8 km at night. The tweek reflection dropped significantly to 78.1 km during sunrise. The equivalent electron density varies from 21.6 to 27.4 cm^-3. Analysis revealed that the propagation distance varies from 500 to 8700 km. Simulation results of attenuation of tweeks propagating in the Earth-ionosphere waveguide for modes m=1-3 are also presented. Moreover, observations of early VLF perturbations on the NWC (19.8 kHz) signal received at Malaysia are presented. We examine the characteristics of both amplitude and phase signatures of early VLF perturbations on a great circle path (GCP) near equatorial regions. The average recovery time for the observed early VLF perturbations is ~160 s, with just a few cases possessing the longer decay time (~20 minutes) associated with large scale gas discharges referred to as gigantic blue jet observation. Unlike previous studies of early VLF events, an equal distribution of positive and negative amplitude changes are observed.

Smoke emitted from wildfires in Central Asia have traditionally impact on the change of land use/land cover, air quality, and climate. Smoke is also important on Earth radiation balance. Direct radiative forcing due to smoke can be large and might indirectly affect global climate. Smoke particles consists of several inorganic and carbonaceous species, including black carbon clusters, fly ash, and mineral dust. Each smoke particle have different role on the radiative forcing, which has positive (heating) forcing and negative (cooling) forcing. Thus, we are interested in the impact of smoke on radiative energy balance by the change of radiative forcing of major smoke components in Central Asia. MODIS fire product (MCD14) and CERES data are used to evaluate net radiative forcing due to smoke. During fire events, negative radiative forcing is dominant, which implies smoke causes cooling the radiative balance. However, each component consisting smoke plays a different role in radiative forcing. In this study, we demonstrate a couple of samples for smoke-laden conditions to estimate radiative forcing.

While Mercury does not possess an atmosphere, it does possess a tenuous exosphere. This exosphere is composed ions which include H⁺ liberated from the surface of Mercury by physical collisions of micrometeorites or high-energy ion precipitation from the solar wind (sputtering), and also, but to a much smaller degree, through the photonic excitation of surface atoms [3,4]. In addition to this exosphere, Mercury also possesses a magnetic field which shields a portion of its surface, particularly its equatorial region, from direct interference from the solar wind. The distribution of these constituent ions in the exosphere is not homogenous. Indeed, there is a noted asymmetry in the presence of Na⁺ planet, and even then there exists a North/South asymmetry among the densities as well [2]. Leblanc and Johnson, 2009, show in a model that over the course of a Mercurian year, the exospheric concentrations and distributions of Na+ in the exosphere change as Mercury’s highly elliptical orbit alternatively moves towards or away from the sun. Building off of that, the author proposes to compare the effects of solar conditions of the exosphere between regular exposure to solar radiation and ions and exposure to a Coronal Mass Ejection (CME). A CME is the sudden release of material from the corona of the sun. The density and energy of the material released is higher than regular solar wind, sometimes by as much as an order of magnitude. The proximity of Mercury to the sun means that it experiences CMEs more often than most planets, and those that it does experience are less attenuated, by density, because of Mercury’s proximity. Using a Multifluid Magnetohydrodynamic model, it would be possible to simulate the interaction of the Mercurian exosphere to regular solar radiation and a CME event. This simulation would be conducted using the main constituents of the Mercurian exosphere, H⁺ Na⁺ as well as Mg⁺ contract or expand as a result of more ion sputtering from the surface? Does this altered exosphere show any significant changes in its optical depth and diffusivity, with respect to the wavelengths usually absorbed and scattered by H⁺, as well as much heavier ions of Na⁺. The intent is to discern how the exosphere reacts under CME conditions. Does it, Na⁺+ and Mg⁺?