Satellite Detection of Smoke Aerosols Over a Snow/Ice Surface by TOMS

The use of TOMS (Total Ozone Mapping Spectrometer) satellite data demonstrates the recently developed technique of using satellite UV radiance measurements to detect absorbing tropospheric aerosols is effective over snow/ice surfaces. Instead of the traditional single wavelength (visible or infrared) method of measuring tropospheric aerosols, this method takes advantage of the wavelength dependent reduction in the backscattered radiance due to the presence of absorbing aerosols over snow/ice surfaces. An example of the resulting aerosol distribution derived from TOMS data is shown for an August 1998 event in which smoke generated by Canadian forest fires drifts over and across Greenland. As the smoke plume moved over Greenland, the TOMS observed 380 nm reflectivity over the snow/ice surface dropped drastically from 90-100% down to 30-40%. To study the effects of this smoke plume in both the UV and visible regions of the spectrum, we compared a smoke-laden spectrum taken over Greenland by the high spectral resolution (300 to 800 nm) GOME instrument with one that is aerosol-free. We also discuss the results of modeling the darkening effects of various types of absorbing aerosols over snow/ice surfaces using a radiative transfer code. Finally, we investigated the history of such events by looking at the nearly twenty year record of TOMS aerosol index measurements and found that there is a large interannual variability in the amount of smoke aerosols observed over Greenland. This information will be available for studies of radiation and transport properties in the Arctic

Profile shape dependence in backscattered ultraviolet satellite retrievals of total ozone

Total ozone operational algorithms use climatological mean ozone profiles. When the actual ozone profiles have significantly different shapes versus the climatology and the solar zenith angles are large, retrieved total ozone will have an error. Recalibrated SBUV profiles are used to estimate this error. Preliminary results suggest that, on the average, the change and variation in significant profiles shapes can to a large degree be estimated by the SBUV derived profiles. Preliminary results suggest the average error in the report algorithm ozone trend (trend in reported ozone) from profile shape is relatively small during the north hemisphere winter (less than 2 percent) for solar zenith angles less than 82 degrees (for 60 degrees North Latitude)

Postlaunch Performance of the Suomi National Polar-Orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) Nadir Sensors

The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected

The Stem Cell Phenotype of Aggressive Breast Cancer Cells

Aggressive cancer cells are characterized by their capacity to proliferate indefinitely and to propagate a heterogeneous tumor comprised of subpopulations with varying degrees of metastatic propensity and drug resistance properties. Particularly daunting is the challenge we face in the field of oncology of effectively targeting heterogeneous tumor cells expressing a variety of markers, especially those associated with a stem cell phenotype. This dilemma is especially relevant in breast cancer, where therapy is based on traditional classification schemes, including histological criteria, differentiation status, and classical receptor markers. However, not all patients respond in a similar manner to standard-of-care therapy, thereby necessitating the need to identify and evaluate novel biomarkers associated with the difficult-to-target stem cell phenotype and drug resistance. Findings related to the convergence of embryonic and tumorigenic signaling pathways have identified the embryonic morphogen Nodal as a promising new oncofetal target that is reactivated only in aggressive cancers, but not in normal tissues. The work presented in this paper confirms previous studies demonstrating the importance of Nodal as a cancer stem cell molecule associated with aggressive breast cancer, and advances the field by providing new findings showing that Nodal is not targeted by standard-of-care therapy in breast cancer patients. Most noteworthy is the linkage found between Nodal expression and the drug resistance marker ATP-binding cassette member 1 (ABCA1), which may provide new insights into developing combinatorial approaches to overcome drug resistance and disease recurrence

Enhanced Deep Blue Aerosol Retrieval Algorithm: The Second Generation

The aerosol products retrieved using the MODIS collection 5.1 Deep Blue algorithm have provided useful information about aerosol properties over bright-reflecting land surfaces, such as desert, semi-arid, and urban regions. However, many components of the C5.1 retrieval algorithm needed to be improved; for example, the use of a static surface database to estimate surface reflectances. This is particularly important over regions of mixed vegetated and non- vegetated surfaces, which may undergo strong seasonal changes in land cover. In order to address this issue, we develop a hybrid approach, which takes advantage of the combination of pre-calculated surface reflectance database and normalized difference vegetation index in determining the surface reflectance for aerosol retrievals. As a result, the spatial coverage of aerosol data generated by the enhanced Deep Blue algorithm has been extended from the arid and semi-arid regions to the entire land areas

The Stem Cell Phenotype of Aggressive Breast Cancer Cells

Aggressive cancer cells are characterized by their capacity to proliferate indefinitely and to propagate a heterogeneous tumor comprised of subpopulations with varying degrees of metastatic propensity and drug resistance properties. Particularly daunting is the challenge we face in the field of oncology of effectively targeting heterogeneous tumor cells expressing a variety of markers, especially those associated with a stem cell phenotype. This dilemma is especially relevant in breast cancer, where therapy is based on traditional classification schemes, including histological criteria, differentiation status, and classical receptor markers. However, not all patients respond in a similar manner to standard-of-care therapy, thereby necessitating the need to identify and evaluate novel biomarkers associated with the difficult-to-target stem cell phenotype and drug resistance. Findings related to the convergence of embryonic and tumorigenic signaling pathways have identified the embryonic morphogen Nodal as a promising new oncofetal target that is reactivated only in aggressive cancers, but not in normal tissues. The work presented in this paper confirms previous studies demonstrating the importance of Nodal as a cancer stem cell molecule associated with aggressive breast cancer, and advances the field by providing new findings showing that Nodal is not targeted by standard-of-care therapy in breast cancer patients. Most noteworthy is the linkage found between Nodal expression and the drug resistance marker ATP-binding cassette member 1 (ABCA1), which may provide new insights into developing combinatorial approaches to overcome drug resistance and disease recurrence

Comparison of TOMS and AVHRR volcanic ash retrievals from the August 1992 eruption of Mt. Spurr

On August 19, 1992, the Advanced Very High Resolution Radiometer (AVHRR) onboard NOAA-12 and NASA\u27s Total Ozone Mapping Spectrometer (TOMS) onboard the Nimbus-7 satellite simultaneously detected and mapped the ash cloud from the eruption of Mt. Spurr, Alaska. The spatial extent and geometry of the cloud derived from the two datasets are in good agreement and both AVHRR split window IR (11–12µm brightness temperature difference) and the TOMS UV Aerosol Index (0.34–0.38µm ultraviolet backscattering and absorption) methods give the same range of total cloud ash mass. Redundant methods for determination of ash masses in drifting volcanic clouds offer many advantages for potential application to the mitigation of aircraft hazards

Nimbus-7 TOMS Version 7 Calibration

This report describes an improved instrument characterization used for the Version 7 processing of the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) data record. An improved internal calibration technique referred to as spectral discrimination is used to provide long-term calibration precision of +/- 1%/decade in total column ozone amount. A revised wavelength scale results in a day one calibration that agrees with other satellite and ground-based measurements of total ozone, while a wavelength independent adjustment of the initial radiometric calibration constants provides good agreement with surface reflectivity measured by other satellite-borne ultraviolet measurements. The impact of other aspects of the Nimbus-7 TOMS instrument performance are also discussed. The Version 7 data should be used in all future studies involving the Nimbus-7 TOMS measurements of ozone. The data are available through the NASA Goddard Space Flight Center's Distributive Active Archive Center (DAAC)

Detection of volcanic ash clouds from Nimbus 7/total ozone mapping spectrometer

Measured radiances from the Version 7 reprocessing of the Nimbus 7/total ozone mapping spectrometer (TOMS) 340- and 380-nm channels are used to detect absorbing particulates injected into the atmosphere after the El Chichon eruption on April 4, 1982. It is shown that while the single-channel reflectivity determined from the 380-nm channel is able to detect clouds and haze composed of nonabsorbing aerosols, the spectral contrast between the 340- and 380-nm channels is sensitive to absorbing particulates such as volcanic ash, desert dust, or smoke from biomass burning. In this paper the spectral contrast between these two channels is used to detect the volcanic ash injection into the atmosphere and to track its evolution for several days. The movement of the ash clouds is shown to be consistent with the motions expected from the National Centers for Environmental Prediction (NCEP)-derived balanced wind fields in the troposphere and lower stratosphere. The movement of the volcanic SO2 cloud detected from TOMS data was also in agreement with the NCEP wind at higher altitudes of up to 100–10 mbar. The vertical wind shear in the neighborhood of the eruption site resulted in a clear separation of the ash and SO2 clouds. The location and movement of the ash cloud are consistent with information obtained by the advanced very high resolution radiometer (AVHRR) instrument on board the NOAA 7 satellite and to ground reports of ash fall

Earth Probe Total Ozone Mapping Spectrometer (TOMS) Data Product User's Guide

Two data products from the Earth Probe Total Ozone Mapping Spectrometer (EP/TOMS) have been archived at the Distributed Active Archive Center, in the form of Hierarchical Data Format files. The EP/ TOMS began taking measurements on July 15, 1996. The instrument measures backscattered Earth radiance and incoming solar irradiance; their ratio is used in ozone retrievals. Changes in the reflectivity of the solar diffuser used for the irradiance measurement are monitored using a carousel of three diffusers, each exposed to the degrading effects of solar irradiation at different rates. The algorithm to retrieve total column ozone compares measured Earth radiances at sets of three wavelengths with radiances calculated for different total ozone values. The initial error in the absolute scale for TOMS total ozone is 3 percent, the one standard deviation random error is 2 percent, and the drift is less than 0.5 percent over the first year of data. The Level-2 product contains the measured radiances, the derived total ozone amount, and reflectivity information for each scan position. The Level-3 product contains daily total ozone and reflectivity in a 1-degree latitude by 1.25 degrees longitude grid. Level-3 files containing estimates of LTVB at the Earth surface and tropospheric aerosol information are also available, Detailed descriptions of both HDF data-files and the CD-ROM product are provided