A New Theory of Lapse-Rate

A new type of vertical motion of air different from penetrative convection is discussed. For small vertical displacements the motion is assumed to be similar to that in long gravitational waves, the volume of an element remaining constant during the displacement. Vertical motion of this type is the result of differences of pressure set up in the vertical direction and the pressures on an element in the other principal directions do not alter during the process of small displacement. As a result of the change in pressure, the molecular energy of the element is altered which results in a change of temperature, and consequently in a lapse-rate

Energy and Water Cycles in the Third Pole

As the most prominent and complicated terrain on the globe, the Tibetan Plateau (TP) is often called the “Roof of the World”, “Third Pole” or “Asian Water Tower”. The energy and water cycles in the Third Pole have great impacts on the atmospheric circulation, Asian monsoon system and global climate change. On the other hand, the TP and the surrounding higher elevation area are also experiencing evident and rapid environmental changes under the background of global warming. As the headwater area of major rivers in Asia, the TP’s environmental changes—such as glacial retreat, snow melting, lake expanding and permafrost degradation—pose potential long-term threats to water resources of the local and surrounding regions. To promote quantitative understanding of energy and water cycles of the TP, several field campaigns, including GAME/Tibet, CAMP/Tibet and TORP, have been carried out. A large amount of data have been collected to gain a better understanding of the atmospheric boundary layer structure, turbulent heat fluxes and their coupling with atmospheric circulation and hydrological processes. The focus of this reprint is to present recent advances in quantifying land–atmosphere interactions, the water cycle and its components, energy balance components, climate change and hydrological feedbacks by in situ measurements, remote sensing or numerical modelling approaches in the “Third Pole” region

Improved SST-precipitation intraseasonal relationships in the ECMWF coupled climate reanalysis

The European Centre for Medium-range Weather Forecasts (ECMWF) has produced the ocean-atmosphere coupled reanalysis for the 20th century CERA-20C, following on from the similar, but atmosphere-only, reanalysis ERA-20C. Here we demonstrate the capability of CERA-20C in producing more physically consistent ocean and atmosphere boundary conditions, by focusing on sea surface temperature (SST)-precipitation intra-seasonal relationships. CERA-20C reproduces well the observed SST-precipitation correlations, while these relationships are poorly represented in ERA-20C, with the greatest discrepancies in the early 1900s. The improved relationships in CERA-20C are due to intra-seasonal improvements in SST that are not present in the external HadISST2 product. In CERA-20C, SST-precipitation relationships are slightly weaker in the 1900s than in the 2000s, mainly due to differences in the assimilated observation density. We also find that the coupled model initialized from CERA-20C in the 2000s realistically simulates these relationships, while relaxing SST towards HadISST2 tends to damp these relationships. CERA-20C has improved mean and variance in precipitation over ERA-20C, but these are mostly due to improvements in the atmospheric model and not due to coupled feedbacks

Comparison of ozone profiles from DIAL, MLS, and chemical transport model simulations over Río Gallegos, Argentina, during the spring Antarctic vortex breakup, 2009

This study evaluates the agreement between ozone profiles derived from the ground-based differential absorption lidar (DIAL), satellite-borne Aura Microwave Limb Sounder (MLS), and 3-D chemical transport model (CTM) simulations such as the Model for Interdisciplinary Research on Climate (MIROC-CTM) over the Atmospheric Observatory of Southern Patagonia (Observatorio Atmosférico de la Patagonia Austral, OAPA; 51.6°S, 69.3°W) in Río Gallegos, Argentina, from September to November 2009. In this austral spring, measurements were performed in the vicinity of the polar vortex and inside it on some occasions; they revealed the variability in the potential vorticity (PV) of measured air masses. Comparisons between DIAL and MLS were performed between 6 and 100hPa with 500km and 24h coincidence criteria. The results show a good agreement between DIAL and MLS with mean differences of ±0.1ppmv (MLS-´DIAL, n,=-) between 6 and 56hPa. MIROC-CTM also agrees with DIAL, with mean differences of ±0.3ppmv (MIROC-CTM-´DIAL, n,=-23) between 10 and 56hPa. Both comparisons provide mean differences of 0.5ppmv (MLS) to 0.8-0.9ppmv (MIROC-CTM) at the 83-100hPa levels. DIAL tends to underestimate ozone values at this lower altitude region. Between 6 and 8hPa, the MIROC-CTM ozone value is 0.4-0.6ppmv (5-8%) smaller than those from DIAL. Applying the scaled PV (sPV) criterion for matching pairs in the DIAL-MLS comparison, the variability in the difference decreases 21-47% between 10 and 56hPa. However, the mean differences are small for all pressure levels, except 6hPa. Because ground measurement sites in the Southern Hemisphere (SH) are very sparse at mid-to high latitudes, i.e., 35-60°S, the OAPA site is important for evaluating the bias and long-Term stability of satellite instruments. The good performance of this DIAL system will be useful for such purposes in the future.Fil: Sugita, Takafumi. National Institute for Environmental Studies; JapónFil: Akiyoshi, Hideharu. National Institute for Environmental Studies; JapónFil: Wolfram, Elian Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Salvador, Jacobo Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; Argentina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Ohyama, Hirofumi. National Institute for Environmental Studies; Japón. Nagoya University; JapónFil: Mizuno, Akira. Nagoya University; Japó

Energy and Water Cycles in the Third Pole

The energy and water cycles in the Third Pole have great impacts on the atmospheric circulation, Asian monsoon system and global climate change [...

A comparative analysis of aerosol microphysical, optical and radiative properties during the Spring Festival holiday over Beijing and surrounding regions

Using ground-based data, meteorological observations, and atmospheric environmental monitoring data, a comparative analysis of the microphysical and optical properties, and radiative forcing of aerosols was conducted between three stations in different developed environments during a severe air pollution episode during the Spring Festival over Beijing. During the most polluted period, the daily peak values of the aerosol optical depth were ~1.62, ~1.73, and ~0.74, which were about 2.6, 2.9, and 2.1 times higher than the background levels at the CAMS, Xianghe, and Shangdianzi sites, respectively. The daily peak values of the single scattering albedo were ~0.95, ~0.96, and ~0.87. The volume of fine-mode particles varied from 0.04 to 0.21 µm3 µm-2, 0.06 to 0.17 µm3 µm-2, and 0.01 to 0.10 µm3 µm-2, which were about 0.3 to 5.8, 1.1 to 4.7, and 1.2 to 8.9 times greater than the background values, respectively. The daily absorption aerosol optical depth was ~0.01 to ~0.13 at CAMS, ~0.03 to ~0.14 at Xianghe, and ~0.01 to ~0.09 at Shangdianzi, and the absorption Ångström exponents reflected a significant increase in organic aerosols over CAMS and Xianghe and in black carbon over Shangdianzi. Aerosol radiative forcing at the bottom of the atmosphere varied from -20 to -130, -40 to -150, and -10 to -110 W m-2 for the whole holiday period, indicating the cooling effect. The potential source contribution function and concentration-weighted trajectory analysis showed that Beijing, the southern parts of Hebei and Shanxi, and the central northern part of Shandong contributed greatly to the pollution

Design of the NIPR trajectory model

Kinematic and isentropic trajectory models developed at the National Institute of Polar Research(NIPR) are compared with METEX developed at the Center for Global Environmental Research, National Institute for Environmental Studies(CGER/NIES). The NIPR model shows good agreement with METEX both in the kinematic and isentropic trajectories. An intercomparison between the tra-jectories computed with different datasets is also performed using the NIPR model, and shows that the accuracy of the trajectory is far more sensitive to the difference of the dataset used than to the difference of trajectory model

On Atmospheric Lapse Rates

We have derived and summarized and most important atmospheric temperature lapse rates. ALRs essentially govern vertical atmospheric air stability and creation of some cloud types. The sensitivity analysis of various atmospheric lapse rates and their dependence on actual ideal-gas air properties and gravitational attraction was conducted for the first time to the best of our knowledge. SALR, which has DALR as the upper asymptote, showed steepest decrease at around 9 degrees Celsius then flattening out and apparently approaching another asymptotic solution which has not been investigated as it falls outside of the terrestrial temperature range. ISA lapse rates are adopted atmospheric standards and hence do not depend on actual conditions. We have also analyzed the dependence of DPLR on air temperatures and moisture content. Understanding thermodynamics and dynamics of atmospheric moist air and phase transitions is of fundamental importance for safety and economy of flight operations and aircraft performance

Optical properties of different aerosol types: seven years of combined Raman-elastic backscatter lidar measurements in Thessaloniki, Greece

We present our combined Raman/elastic backscatter lidar observations which were carried out at the EARLINET station of Thessaloniki, Greece, during the period 2001–2007. The largest optical depths are observed for Saharan dust and smoke aerosol particles. For local and continental polluted aerosols the measurements indicate high aerosol loads. However, measurements associated with the local path indicate enhanced aerosol load within the Planetary Boundary Layer. The lowest value of aerosol optical depth is observed for continental aerosols, from West directions with less free tropospheric contribution. The largest lidar ratios, of the order of 70 sr, are found for biomass burning aerosols. A significant and distinct correlation between lidar ratio and backscatter related Ångström exponent values were estimated for different aerosol categories. Scatter plot between lidar ratio values and Ångström exponent values for local and continental polluted aerosols does not show a significant correlation, with a large variation in both parameters possibly due to variable absorption characteristics of these aerosols. Finally for continental aerosols with west and northwest directions that follow downward movement when arriving at our site constantly low lidar ratios almost independent of size are found