Using Chandra X-ray, Spitzer mid-IR, and 1.5 GHz radio data, we examine the spatial structure of SNR 3C 391. The X-ray surface brightness is generally anti-correlative with the IR and radio brightness. The multiband data clearly exhibit a heart-shaped morphology and show the multi-shell structure of the remnant. A previously unseen thin brace-like shell on the south detected at 24 μm is projected outside the radio border and confines the southern faint X-ray emission. The leading 24 μm knot on the SE boundary appears to be partly surrounded by soft X-ray emitting gas. The mid-IR emission is dominated by the contribution of the shocked dust grains, which may have been partly destroyed by sputtering. 相似文献
The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term. 相似文献
Halocarbons, such as CFC-11, CFC-12 and HCFC-22, are important trace gases in the atmosphere through their role as greenhouse gases and their influence on stratospheric ozone chemistry. This paper focuses on an initial study using integration of spectral radiance measurements from a spaceborne limb sounding Fourier Transform Spectrometer (FTS) to retrieve these compounds in the upper troposphere and lower stratosphere (UTLS). The instrument employed in this study is the Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E) which obtains spectral data in the altitude range of 6–68 km at an unapodized spectral resolution of 0.025 cm−1. We have used optimal estimation techniques to retrieve vertical information for these compounds using a radiometric approach.
It is shown that significant retrieval information is obtained at up to five measured levels in the UTLS for CFC-11, up to six for CFC-12 and up to two levels for HCFC-22. An initial error analysis indicates significant sensitivity of our retrievals to variability in operationally retrieved pressure and temperature data. For each halocarbon, gain, offset and spectroscopic uncertainties generally each contribute less than 10% to the total error. Finally, tracer correlations are used to compare the datasets to equivalent relationships derived here from version 2 ATMOS data with very good agreements for CFC-12 but with more variability in the CFC-11 comparisons. 相似文献
The CRISTA-NF instrument is the airborne version of the CRISTA satellite infrared limb sounder. It has been successfully flown on the Geophysica research airplane during a test campaign in July 2005, during the SCOUT-O3 Tropical Aircraft Campaign in November/December 2005 and during the AMMA campaign in August 2006. Radiance calibrations of the airborne instrument are more complex compared to the satellite instrument because the vacuum shell of CRISTA-NF is confined by a ZnSe (zinc–selenide) window and the detectors can thermally drift during measurement flights. By comprehensive radiance calibrations with a blackbody source the window’s emissivity and transmissivity are determined and the dependence of the instrument sensitivity on the detector temperature is characterized. Taking these effects into account, the remaining radiance error of the calibration is smaller than 3%. 相似文献