Search Results (6)

Global CO₂ concentrations continue to rise despite significant efforts to decarbonize and reduce greenhouse gas emissions. This paper examines the role of sustainable business in reducing and limiting global CO₂ concentrations based on daily CO₂ data from the Mauna Loa Observatory. Based on the theory of the carbon cycle, factors considered significant in determining global CO₂ concentrations include emissions, affected by economic variables like the crude oil price and Dow Jones Sustainability Index but also absorption capacity, affected through biomass growth by astronomical variables such as total solar irradiance and cosmic rays. Considering pair-wise correlations between variables, particular attention is drawn to the fact that in the COVID-19 pandemic, when everyone was working from home, cars were not allowed on the roads, and planes were not flying, the correlation between the Dow Jones Sustainability Index and the global CO₂ concentration was negative. The article tests the hypothesis that business can be a force for good and make a meaningful contribution towards reducing global CO₂ concentrations. To this end, it offers an integrated model of global CO₂ concentrations built according to the theory of the carbon cycle based on 2195 daily observations, including all the variables outlined above. The results confirm the hypothesis that business, expressed in the form of Dow Jones Sustainability Index, can play a role in reducing the global CO₂ concentrations. A range of policy conclusions is drawn. Full article

A sun photometer is a type of photometer that points at the sun, and it has been playing an increasingly important role in characterizing aerosols across the world. As long as the solar photometer is accurately calibrated, the optical thickness of the aerosol can be obtained from the measured value of this device. When the calibration of a single instrument is not accurate, the inversion quantity varies greatly. The calibration constant of the sun photometer changes during its use process; thus, calibrations are frequently needed in order to ensure the accuracy of the measured value. The calibration constant of the solar photometer is usually determined using the Langley method. Internationally, AERONET has two Langley calibration stations: the Mauna Loa observatory in the United States and the Izaña observatory in Spain. So far, the International Comparison and Calibration System has been established in Beijing, similar to AERONET at GSFC, but the Langley calibration system has not yet been established. Therefore, it is necessary to select a suitable calibration station in China. This paper studies the requirements of the calibration station using the Langley method. We used long-term records of satellite-derived measurements and survey data belonging to the aerosol optical thickness data of SNPP/VIIRS, CERES, MERRA-2, etc., in order to gain a better understanding of whether these stations are suitable for calibration. From the existing astronomical observation stations, meteorological stations, and the Sun–Sky Radiometer Observation Network (SONET) observation stations in China, the qualified stations were selected. According to the statistical data from the Ali observatory, the monthly average of clear sky is 20.21 days, and it is always greater than 15 days. The monthly average of aerosol is not more than 0.15 and is less than 0.3. We believe that the atmosphere above the Ali observatory is stable, and the results show that the Ali observatory has excellent weather conditions. This study can provide a selection of calibration sites for solar photometer calibrations in China that may need to be further characterized and evaluated, and at the same time provide a method to exclude unsuitable calibration sites. Full article

Carbonaceous aerosols emitted from biomass burning influence radiative forcing and climate change. Of particular interest are emissions from high-latitude peat burning because amplified climate change makes the large carbon mass stored in these peatlands more susceptible to wildfires and their emission can affect cryosphere albedo and air quality after undergoing transport. We combusted Siberian peat in a laboratory biomass-burning facility and characterized the optical properties of freshly emitted combustion aerosols and those photochemically aged in an oxidation flow reactor (OFR) with a three-wavelength photoacoustic instrument. Total particle count increased with aging by a factor of 6 to 11 while the total particle volume either changed little (<8%) for 19 and 44 days of equivalent aging and increased by 88% for 61 days of equivalent aging. The aerosol single-scattering albedo (SSA) of both fresh and aged aerosol increased with the increasing wavelength. The largest changes in SSA due to OFR aging were observed at the shortest of the three wavelengths (i.e., at 405 nm) where SSA increased by less than ~2.4% for 19 and 44 days of aging. These changes were due to a decrease in the absorption coefficients by ~45%, with the effect on SSA somewhat reduced by a concurrent decrease in the scattering coefficients by 20 to 25%. For 61 days of aging, we observed very little change in SSA, namely an increase of 0.31% that was caused a ~56% increase in the absorption coefficients that was more than balanced by a somewhat larger (~71%) increase in the scattering coefficients. These large increases in the absorption and scattering coefficients for aging at 7 V are at least qualitatively consistent with the large increase in the particle volume (~88%). Overall, aging shifted the absorption toward longer wavelengths and decreased the absorption Ångström exponents, which ranged from ~5 to 9. Complex refractive index retrieval yielded real and imaginary parts that increased and decreased, respectively, with the increasing wavelength. The 405 nm real parts first increased and then decreased and imaginary parts decreased during aging, with little change at other wavelengths. Full article

The scaling properties of turbulent flows are well established in the inertial sub-range. However, those of the synoptic-scale motions are less known, also because of the difficult analysis of data presenting nonstationary and periodic features. Extensive analysis of experimental wind speed data, collected at the Mauna Loa Observatory of Hawaii, is performed using different methods. Empirical Mode Decomposition, interoccurrence times statistics, and arbitrary-order Hilbert spectral analysis allow to eliminate effects of large-scale modulations, and provide scaling properties of the field fluctuations (Hurst exponent, interoccurrence distribution, and intermittency correction). The obtained results suggest that the mesoscale wind dynamics owns features which are typical of the inertial sub-range turbulence, thus extending the validity of the turbulent cascade phenomenology to scales larger than observed before. Full article

Hawai’i Island often receives extreme (UV Index ≥ 11) solar ultraviolet radiation (UVR). While the UV Index (UVI) has been measured since 1997 at Hawai’i’s high-altitude Mauna Loa Observatory (MLO), measurements where people live and recreate are rare. We measured UVI on the face of a rotating mannequin head with UVR sensors at its eyes, ears and cheeks while simultaneously measuring the UVI with a zenith-facing sensor at MLO and seven sites at or near sea level from 19 July to 14 August 2018. The mannequin sensors received higher UVR at midmorning and midafternoon than at noon. For example, at sea level the peak UVI at the left cheek was 5.2 at midmorning and 2.9 at noon, while the horizontal UVI at noon was 12.7. Our measurements were supplemented with wide-angle (190° and 360°) sky photographs and UV images of the mannequin head. Because the UVI applies to horizontal surfaces, people in tropical and temperate latitudes should be informed that their face may be more vulnerable to UVR at midmorning and midafternoon than at noon. Finally, our instruments provided opportunities to measure unexpected UVR-altering events, including rare biomass smoke over MLO and spectroscopic measurements of substantial UVR-absorbing sulfur dioxide in the eruption plume of the Kilauea volcano. Full article

The surface-wind speed influences on aerosol optical depth (AOD), derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua daily observations over the central North Pacific during the period 2003–2016, have been investigated in this study. The cloud coverage is relatively low over the present investigation area compared to other marine areas, which favors AOD derived from passive remote sensing from space. In this study, we have combined MODIS AOD with 2 m wind speed (U_2m) on a satellite-pixel basis, which has been interpolated from National Centers for Environmental Prediction (NCEP) reanalysis. In addition, daily averaged AOD derived from Aerosol Robotic Network (AERONET) measurements in the free-troposphere at the Mauna Loa Observatory (3397 m above sea level), Hawaii, was subtracted from the MODIS column AOD values. The latter was to reduce the contribution of aerosols above the planetary boundary layer. This study shows relatively strong power-law relationships between MODIS mean AOD and surface-wind speed for marine background conditions in summer, fall and winter of the current period. However, previous established relationships between AOD and surface-wind speed deviate substantially. Even so, for similar marine conditions the present relationship agrees reasonable well with a power-law relationship derived for north-east Atlantic conditions. The present MODIS retrievals of AOD in the marine atmosphere agree reasonably well with ground-based remote sensing of AOD. Full article