Abstract. This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI) on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout) and near real-time (NRT) availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.

No abstract

No abstract

[1] We have made daily global maps that cover both polar and equatorial regions of Mars for L s 135°-360°and 0°-111°using the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red and blue wide-angle swaths taken from May 1999 to January 2001. We study the seasonal distribution of condensate clouds and dust clouds during roughly 1 Martian year using these daily global maps. We present the development and decay of the tropical cloud belt and the polar hoods, the spatial and temporal distributions of lee waves and spiral clouds, and an unusual ''aster'' cloud above the volcanoes, consisting of rays around a central disk, like the flower. The tropical cloud belt contains mostly fibrous clouds during northern spring/early summer and convective clouds during middle/ late northern summer. The detailed development and decay of the tropical cloud belt is nonuniform in longitude. Two distinct stormy periods in late summer precede the formation of the north and south circumpolar hoods. The north polar storms in late summer resemble baroclinic frontal systems on Earth but contain both dust and condensate clouds. Spiral clouds occur only in the northern high latitudes and only during northern spring and summer. The north polar hood displays a stationary wave number two structure during the fall and winter. The south polar hood has fewer streak clouds and lee wave clouds than the north polar hood. During this particular year the lee wave cloud abundance in the south had two peaks (in early fall and late winter), and the lee wave cloud abundance in the north had one peak (in early fall).

A global dust storm occurred on Mars between June and October 2001. The storm began near Hellas just before southern spring equinox (∼Ls = 177°). Local storms, likely forced by a combination of slope‐flow and ice cap thermal contrasts, were observed to propagate along the northwestern rim of Hellas, apparently triggering the global storm. Cap‐edge storm activity for much of late southern winter was similar in 2001 to one Mars year earlier; however, a very large storm propagated into the basin just after Ls = 177°. Subsequently, the total area of storm activity in 2001 was roughly double that of the previous year. For about 10 days, dust lifting was limited to the Hellas region. As additional storms propagated into Hellas, activity built and extended northward into Syrtis and eastward into Hesperia. It is not clear whether transport or spreading of lifting were of greatest importance for expansion. At Ls = 185° the storm began to spread rapidly to the east, along a line from the southern pole to the northern tropics. Essentially no storm propagation to the west occurred, yielding strong zonal asymmetry of expansion. As the dust storm reached the western edge of Tharsis, secondary dust lifting centers developed in Daedalia and Solis (southeastern Tharsis). Subsequently, the storm rapidly encompassed the planet (by Ls = 193°). Once fully global, the Syria/Solis/Daedalia lifting center appeared to dominate (on the basis of cloud top morphology), with Hellas quiescent. By Ls = 212°, lifting could no longer be discerned. Thereafter, dust haze appeared uniform and diffuse, and decay appeared to have set in.

No abstract

may cause power blackouts. [1] Moreover, the refrigerant gases used in air conditioners are one of the largest contributors to greenhouse gas emissions. [2] Passive cooling, e.g., cooling with no power input and without greenhouse gas emission, provides an attractive solution to alleviate the power demands as well as negative environmental impact of building cooling. Recent theoretical and experimental demonstrations of subambient daytime radiative cooling (SDRC) represent a breakthrough in realizing passive daytime cooling. [3-21] These radiative cooling materials exploit the infrared transparency window of the atmosphere, in the wavelength range of 8-13 µm, to directly transmit heat from an object at ambient temperature, through blackbody radiation, to the cold outer space which has a temperature of 3 K (−270 °C). This radiation effect, in fact, is what causes one to feel chilly when staying outside in summer nights. However, to generate subambient daytime cooling under direct sunlight using the same effect, the materials must overcome the heating generated by the direct sunshine. In

Articular cartilage is the remarkable bearing material of diarthrodial joints. Experimental measurements of its friction coefficient under various configurations have demonstrated that it is load-dependent, velocity-dependent, and time-dependent, and it can vary from values as low as 0.002 to as high as 0.3 or greater. Yet, many studies have suggested that these frictional properties are not dependent upon the viscosity of synovial fluid. In this paper, a theoretical formulation of a boundary friction model for articular cartilage is described and verified directly against experimental results in the configuration of confined compression stress-relaxation. The mathematical formulation of the friction model can potentially explain many of the experimentally observed frictional responses in relation to the pressurization of the interstitial fluid inside cartilage during joint loading, and the equilibrium friction coefficient which prevails in the absence of such pressurization. In this proposed model, it is also hypothesized that surface porosities play a role in the regulation of the frictional response of cartilage. The good agreement between theoretical predictions and experimental results of this study provide support for the proposed boundary friction formulation.