Abstract

In situ, airborne and satellite measurements are used to characterize the structure of water vapor in the lower tropical troposphere—below the height, (Formula presented.) of the triple-point isotherm, (Formula presented.) The measurements are evaluated in light of understanding of how lower-tropospheric water vapor influences clouds, convection and circulation, through both radiative and thermodynamic effects. Lower-tropospheric water vapor, which concentrates in the first few kilometers above the boundary layer, controls the radiative cooling profile of the boundary layer and lower troposphere. Elevated moist layers originating from a preferred level of convective detrainment induce a profile of radiative cooling that drives circulations which reinforce such features. A theory for this preferred level of cumulus termination is advanced, whereby the difference between (Formula presented.) and the temperature at which primary ice forms gives a ‘first-mover advantage’ to glaciating cumulus convection, thereby concentrating the regions of the deepest convection and leading to more clouds and moisture near the triple point. A preferred level of convective detrainment near (Formula presented.) implies relative humidity reversals below (Formula presented.) which are difficult to identify using retrievals from satellite-borne microwave and infrared sounders. Isotopologues retrievals provide a hint of such features and their ability to constrain the structure of the vertical humidity profile merits further study. Nonetheless, it will likely remain challenging to resolve dynamically important aspects of the vertical structure of water vapor from space using only passive sensors. © 2017 The Author(s) Document type: Part of book or chapter of book

Abstract

Two geophysical surveys were conducted over a vitrified clay pipeline (VCP) that was used to transfer liquid radioactive waste from the 224-U Building to the 216-U-8 and 216-U-12 cribs. The objectives of the surveys were to locate the VCP in the northern site, locate the bends in the VCP in the southern site, and locate possible utilities or pipelines at both sites. Ground-penetrating radar (GPR) was the method chosen for the surveys. Electromagnetic induction (EMI) was also used at the southern site to map the extent of a possible pipeline. It is very difficult to detect most VCPs with GPR, however, excavation boundaries for the pipeline are often discernible. The VCP was not identified in the GPR data at the northern site. Its anticipated depth was 10--12 ft. The VCP at the southern site appears to be much shallower. The data suggest it may be 5 ft or less below the surface in places. The edges of the excavation from N100 to N190 are between E120 and E135 and were quite distinct in the data. However, the excavation boundaries weren`t apparent north of N190, suggesting that the VCP bends to the north near N200. Several profiles were extended beyond N200.more » These profiles detected a linear, with the characteristic signature of a pipeline, approximately 3 ft below the surface. There was no previous knowledge of the pipeline. The linear was traced across the entire surface contamination area with an EMI geophysical tool.« le Document type: Report

Abstract

Cirrus clouds have a large influence on the Earth's climate and anthropogenic activities such as aviation can alter their properties. Besides the formation of contrails, indirect effects on naturally occurring cirrus like increased heterogeneous freezing due to exhaust soot particles are discussed in the literature. However, hardly any observational study exists. In this work we present cirrus optical properties measured by an airborne lidar over Europe during the Midlatitude Cirrus experiment (ML-CIRRUS). One half of the cloud cases showed elevated depolarization ratios with a mode difference of 10 percentage points indicating differences in the clouds microphysical properties. Their origin can be traced back to highly frequented air traffic regions, and they show lower in-cloud ice supersaturations. Our analysis reveals no influence of embedded contrails and temperature. These results could be explained by an indirect aerosol effect where heterogeneous freezing is caused by aviation exhaust particles.

Abstract

The damage on supply and drainage water networks is a serious cause of economic disruption for urban systems affected by earthquakes. Among various concerns, the ruptures of sewer pipes and manholes generated by liquefaction determine a particularly severe sanitary hazard and require extensive, costly and time-consuming repairs. Quantitative risk assessment carried out with the characterisation and geographical mapping of seismic hazard, subsoil susceptibility, physical and functional vulnerability of the exposed elements, enables to estimate losses, identify weaknesses, inspire strategies to mitigate the impact of earthquakes and improve resilience. The present study deals with the physical vulnerability of sewer pipelines. Empirical fragility functions are derived from the evidences of liquefaction induced in Urayasu (Japan) by the 2011 Tohoku-Oki earthquake (Mw9.0). The spatial distribution of seismic signals, subsoil characteristics, pipes and surveyed damages are reconstructed in a GIS platform. An articulated methodology is developed to correlate variables and compensate their limited spatial correspondence, exploiting the complete coverage of the area with terrestrial settlements measured by LiDAR and their strong correlation with damage. Finally, ruptures of pipes are probabilistically quantified adopting a common liquefaction severity indicator as engineering demand parameter and measuring the efficiency of relations with statistical tests.

Abstract

Recent earthquakes show that pipeline damage is severe in the areas where permanent ground deformations (e.g., liquefaction zones) occur. Ground movement hazard to pipeline systems can be assessed by using ground displacement measurements around the location of pipelines. There are many different ways of measuring ground displacements after an earthquake occur. This paper compares displacements measured in Avonside area, Christchurch, NZ, by using four different ways with respect to their effects on pipeline damage assessments. They are air photo, satellite, high resolution light detection and ranging (LiDAR) surveys data presented at 4- and 56-m grids acquired before and after the Mw6.2 22 February 2011 earthquake. Avonside area was in the liquefaction zones of the 22 February 2011 earthquake. Where possible, benchmark measurements were also included in the comparisons. In this study, the focus was on asbestos cement and cast iron water pipelines as the length of the pipelines and the number of damages in the study area was much higher compared to other pipe materials, providing sufficient repair rate data passing the screening criteria to develop linear regressions. The correlations between pipeline damage and lateral ground strains were developed by calculating the horizontal strains from these four different type displacements. The comparisons show that satellite imagery is good for estimating total movements but not so good for estimating lateral strains and conversely LiDAR surveys are not so good for estimating total movements, but much better for estimating lateral strains. Hence, pipeline damage correlations with LiDAR calculated strains provide higher determination coefficient (r2) value. The results of comparisons are presented and discussed. © 2018, Springer Science+Business Media B.V., part of Springer Nature.