Assimilation of All-sky Geostationary Satellite Infrared Radiances for Convection-Permitting Initialization and Prediction of Hurricane Joaquin(2015)

Intensity forecasting is one of the most challenging aspects of tropical cyclone(TC) forecasting. This work examines the impact of assimilating high-resolution all-sky infrared radiance observations from geostationary satellite GOES-13 on the convection-permitting initialization and prediction of Hurricane Joaquin(2015) with an ensemble Kalman filter(EnKF)based on the Weather Research and Forecasting(WRF) model. Given that almost all operational global and regional models struggled to capture Hurricane Joaquin(2015)'s intensity, this study examines the potential in improving Joaquin's prediction when assimilating all-sky infrared radiances from GOES-13's water vapor channel. It is demonstrated that, after a few 3-hour cycles assimilating all-sky radiance, the WRF model was able to forecast reasonably well Joaquin's intensity,including its rapid intensification(RI). The improvement was largely due to a more realistic initial hurricane structure with a stronger, warmer, and more compact inner-core. Ensemble forecasts were used to further explore the important physical mechanisms driving the hurricane's RI. Results showed that the RI forecasts were greatly impacted by the initial inner-core vortex structure.

Sunglint Impact on Atmospheric Soundings from Hyperspectral Resolution Infrared Radiances

The mid-wave infrared band （3-5 #rn） has been widely used for atmospheric soundings. The sunglint impact on the atmospheric parameter retrieval using this band has been neglected because the reflected radiances in this band are significantly less than those in the visible band. In this study, an investigation of sunglint impact on the atmospheric soundings was conducted with Atmospheric InfraRed Sounder ob- servation data from 1 July to 7 July 2007 over the Atlantic Ocean. The impact of sunglint can lead to a brightness temperature increase of 1.0 K for the surface sensitive sounding channels near 4.58 #m. This contamination can indirectly cause a positive bias of 4 g kg-1 in the water vapor retrieval near the ocean surface, and it can be corrected by simply excluding those contaminated channels.

Structure, Infrared Radiation Properties and Mssbauer Spectroscopic Investigations of Co_(0.6)Zn_(0.4)Ni_xFe_(2-x)O_4 Ceramics

Ferrite compound Co0.6Zn0.4NixFe2-xO4 was synthesized by solid state reaction. The structure and performance of Co0.6Zn0.4NixFe2-xO4 compounds were studied by Moessbauer spectroscopy, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and infrared radiant tester. Moessbauer spectroscopy and XPS analysis show the valence states and distribution of cations in Co0.6Zn0.4NixFe2-xO4. Zn2＋ has invariably shown preference for the tetrahedral sites, and Ni2＋ has the preference for the octahedral sites. The occupancy of Fe3＋ linearly increases on the tetrahedral sites, and sharply decreases on the octahedral sites with increasing x, owing to its gradual replacement by Ni2＋ on the octahedral sites. It indicates that due to the occupation of octahedral sites by the majority of Ni2＋, Fe3＋ decreasingly migrated from the octahedral sites to the tetrahedral sites and substituted Co3＋ sites, which made the number of Co3＋ in the tetrahedral sites decreasing. According to the measurement results of XRD and the infrared radiant tester analysis, the lattice parameter and infrared radiance have shown a nonlinear variation, exhibiting the infrared average radiance of 0.92 in the 8-14μm waveband, and the results demonstrate that these Co-Zn-Ni spinel ferrites have potential for application in a wide range of infrared heating and drying materials.