Engineering topics

Porter, John N.

Publications and source records attributed to Porter, John N..

5 records

NASA NTRS2001

Aircraft/Surface Derived Aerosol Optical Properties Near Hawaii for Satellite Validation

Due to the complexity of atmospheric aerosol, validation efforts are required to test satellite retrievals. Here we give an overview of our aircraft and ship validation measurements near Hawaii. Some examples of the measurements are shown which illustrate some of the variability we have encountered, This effort is ongoing and can provide important background measurements for satellite validation as well as radiation studies.

Porter, John N.↗

NASA NTRS2001

Measurements of Aerosol, Ocean and Sky Properties at the HOT Site in the Central Pacific

Monthly cruises have been made to the HOT site (approximately 100 km north of Oahu) since October 1988. The goal of these cruises is to make hydrography, chemistry, and biology observations. Measurements are typically made at a near coastal station (Kahe) on the first day to test the equipment and to obtain coastal shallow water (approximately 1500 m) observations. The second and third days are spent at the HOT site. On the morning of the fourth day, measurements are made at the HOT site and noontime measurements are made at the Hale-Aloha station near the mooring before returning to port by early the next morning. The locations of the three stations are Kahe, HOT, and Hale-ALOHA buoy. The routine HOT measurements are available during the summer following the year of the observations. The 1998 measurements will therefore become available during the summer of 1999. The data sets can be obtained at the National Oceanographic Data Center (NODC) or from the HOT web site http://kahana.soest.hawaii.edu/hot/hot_jgofs.html.

Porter, John N.↗

NASA NTRS1997

Developing a Stand Alone Sun Photometer for Ships and Buoys

During November and December 1995 the first Aerosol Characterization Experiment (ACE 1) was carried to characterize the aerosol physical and optical properties in the clean marine atmosphere near Tasmania in the South Pacific. As part of this effort, and with funding from this proposal, we installed a sun photometer on the R/V Discoverer and a spectro-photometer on the NOAA C-130 aircraft.

Porter, John N.↗

NASA NTRS1997

Remote Marine Aerosol: A Characterization of Physical, Chemical and Optical Properties and their Relation to Radiative Transfer in the Troposphere

Our research effort is focused on improving our understanding of aerosol properties needed for optical models for remote marine regions. This includes in-situ and vertical column optical closure and involves a redundancy of approaches to measure and model optical properties that must be self consistent. The model is based upon measured in-situ aerosol properties and will be tested and constrained by the vertically measured spectral differential optical depth of the marine boundary layer, MBL. Both measured and modeled column optical properties for the boundary layer, when added to the free-troposphere and stratospheric optical depth, will be used to establish spectral optical depth over the entire atmospheric column for comparison to and validation of satellite derived radiances (AVHRR).

Clarke, Antony D.↗

NASA NTRS1991

Aerosol size distribution, composition, and CO2 backscatter

The aerosol size distribution, composition, and CO2 backscatter at 10.6 microns (beta-CO2) were measured continuosly at the Mauna Loa Observatory (Hawaii) during January-March and November-December, 1988 periods to compare the characteristics of periods associated with appreciable Asian dust transport to that site (January-March) with those of periods characterized by low-dust condition. The aerosol size distribution in the range 0.15 micron to 7.6 microns was measured at temperatures of 40, 150, and 340 C to differentiate between volatile and nonvolatile aerosols. Large ranges of variability was found in measurements of aerosol size distribution during both periods, but the average distributions were similar for both the high-dust and the low-dust periods. However, values for beta-CO2 were more elevated (by about six times) during periods associated with active Asian dust transport to the observatory site than during the low-dust periods.

Clarke, Antony D.↗