SCIAMACHY limb measurements of NO2, BrO and OClO. Retrieval of vertical profiles: Algorithm,first results,sensitivity and comparison studies

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) measures scattered sun light also in limb viewing mode (i.e. tangential to Earth’s surface and its atmosphere), which allows determining vertical profiles of atmospheric trace gases. First results on the retrieval of NO₂, BrO and OClO profiles from the SCIAMACHY Limb measurements are presented and compared to independent satellite and balloon borne observations.     

Comparison of OClO nadir measurements from SCIAMACHY and GOME

The scanning imaging absorption spectrometer for atmospheric chartography was launched successfully onboard ENVISAT on March 1, 2002. It observes the solar radiation transmitted and backscattered from the atmosphere and reflected from the ground in nadir, limb and occultation viewing modes. Chlorine dioxide (OClO), an important indicator for stratospheric chlorine activation, can be measured in the UV spectral range by differential optical absorption spectroscopy (DOAS).

First results of the DOAS retrieval of OClO slant column densities from the SCIAMACHY nadir measurements are presented and compared to measurements of the global ozone monitoring experiment (GOME), which has successfully measured OClO since 1995. While SCIAMACHY operates in the same orbit, it measures ≈30 min earlier than GOME and has an increased spatial resolution (30 × 60 km² compared to 40 × 320 km² for GOME).     

Wind detection in a microcosm: Ship/aircraft environment sensors

One of the most demanding aspects of a Navy helicopter pilot's job is landing his aircraft on the flight deck of a pitching, rolling, heaving and yawing ship. The complex airwake velocity field associated with the ship and aircraft interface directly affects the pilot's ability to control the aircraft during takeoff, approach, hover, landing, and deck operations. Dynamic Interface (DI) testing is performed to define safe aircraft operational envelopes; however, not all conditions can be realized within the limited test period and asset/condition availability. In addition, exact wind conditions that affect the aircraft cannot be measured with existing wind sensors. These sensors measure wind in the ship's mast area which does not represent the wind flow field encountered by the aircraft. A means of non-intrusively measuring the appropriate wind data is required. This paper presents an overview of the unique aspects of the ship/aircraft interface, the overall naval DI environment and the sensor requirements for measuring this complex environment