The relationship between tree vigor, measured as stem growth per unit of leaf area, and susceptibility to mountain pine beetle attacks was examined in a stocking-level experiment ponderosa (Pinus Laws.) central Oregon. Vigor decreased both density (basal area) area index increased. Low vigor trees were more often attacked by beetles than high trees. Attacks increased below threshold about 100 g wood produced square meter year, corresponding this study basal 21 m 2 ha - or 2.9 -2. For...

Recent concern over possible long term stratospheric changes caused by the introduction of man‐made compounds has increased need for instrumentation that can accurately measure minor constituents. The technique radio spectroscopy at millimeter wavelengths was first used to observe rotational transitions ozone nearly two decades ago, but not been highly developed until recently. We report here on a ground‐based observing which employs millimeter‐wave superheterodyne receiver and multichannel...

Abstract Competition from understory vegetation for water and nutrients can limit productivity of young forest stands. Less is known the effect on long‐term stand growth or soil organic properties. The periodic annual increments (PAIs) basal area, height, volume ponderosa pine ( Pinus Dougl.) in central Oregon at 4‐ 5‐yr intervals was examined a 35‐yr period. Soil C, N, microbial biomass C (MBC) were also quantified after 32 35 yr with without sandy loam pumice (Xeric Vitricryand). Five tree...

Abstract With data from a long-term experiment in which initial stocking of trees and understory vegetation were controlled, we tested the hypothesis that stand growth is directly correlated with development forest canopy; e.g., proportional to canopy leaf area. The was generally supported. Stands ponderosa pine without more rapidly developed area than stands an understory. At very low indices, wood production per unit efficient, particularly where had been removed. Once index exceeded 2.0,...

This article reports measurements of the column density stratospheric chlorine monoxide and presents a complete diurnal record its variation (with 2-hour resolution) obtained from ground-based observations millimeter-wave spectral line at 278 gigahertz. Observations were carried out during October December 1982 Mauna Kea, Hawaii. The results reported here indicate that mixing ratio above 30 kilometers daytime are approximately 20 percent lower than model predictions based on 2.1 parts per...

Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured ground-based 204-gigahertz, millimeter-wave receiver. Data taken at latitude 42 degrees N on 17 days between 10 January 18 February 1980 yield an average oxide column density approximately 1.05 x 10(14) per square centimeter or 2/3 that eight situ balloon flight measurements (excluding anomalously high data 14 July 1977) made over past 4...

We have measured stratospheric perhydroxyl (HO 2 ) by using a sensitive mm‐wave receiver to obtain spectroscopic line profiles of three rotational emission lines in the vicinity 265.8 GHz. The observations were carried out over four days September–October 1982 at Mauna Kea, Hawaii (19.5 N latitude) and yield good agreement with column density vertical distribution predicted above ∼35 km representative two‐dimensional photochemical models employing JPL 82‐57 reaction rates chemistry;...

The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Aircraft Sounder Testbed (NAST) has been developed and deployed on the NASA ER-2 high-altitude aircraft. testbed consists of two co-located cross-track scanning instruments: a Fourier transform interferometer spectrometer (NAST-I) with spectral coverage 3.7-15.5 /spl mu/m passive microwave (NAST-M) 17 channels near oxygen absorption lines at 50-57 GHz 118.75 GHz. provides first coregistered imagery from...

The ozone altitude profile for 25 ≤ z 55 km was measured from McMurdo Station, Antarctica, by ground‐based millimeter‐wave spectrometry, on 34 days between September 12 and October 29, 1986. mixing ratio peaked at altitudes ranging 28 to km, with peak values 5 9 parts per million volume (ppmv). decreased 15±5% (1σ uncertainty) during the period. No significant decrease observed higher altitudes; upper limit any secular trend 33 or 40 is ∼8%. Considerable variability all altitudes, time...

Passive microwave imagine of O2emissions using the 118.75-GHz(1−) resonance has been investigated for tropospheric and stratosphere remote sensing atmospheric temperature precipitation. An imaging millimeter-wave spectrometer (MTS) eight double-sideband channels centered around 118.75-GHz O2 resonance, including a fixed-beam 53.65-GHz radiometer video camera was constructed. The MTS collected data during 33 flights NASA ER-2 high-altitude aircraft in 1986 Genesis Atlantic Lows Experiment...

Abstract. We present a re-analysis of upper stratospheric ClO measurements from the ground-based millimeter-wave instrument January 1992 to February 2012. These are made as part Network for Detection Atmospheric Composition Change (NDACC) Mauna Kea, Hawaii, (19.8° N, 204.5° E). Here, we use daytime and nighttime together form day–night spectrum, which difference in day night profiles is retrieved. results then compared Upper Atmosphere Research Satellite (UARS) Aura Microwave Limb Sounder...

An imaging microwave radiometer with eight double-sideband channels centered on the 118-GHz oxygen resonance was flown a high-altitude aircraft over tropical cyclone in Coral Sea. The measurements clearly resolved an eyewall of strong convection and warm core within eye. Brightness temperatures observed eye were approximately 10 K warmer than those clear air 100 km or more away. This warming extended somewhat beyond highest (most opaque) channel. temperature profile eye, central pressure,...

Measurements of stratospheric N 2 O were made from Mauna Kea in Hawaii June, 1983 and May 1986, by observing thermal emission the molecule a rotational transition at ∼ 1 mm wavelength. Analyses data yield altitude profiles middle upper stratosphere. Useful measurements may be one to two hours. The agree reasonably well with model predictions published satellite data, though we report significantly more near stratopause than shown measurement, stratosphere models. discrepancy between our...

We have measured middle and upper stratospheric HCN using ground‐based mm‐wave emission spectroscopy, during a series of observations made in Mauna Kea, Hawaii, June 1986. find volume mixing ratio 190±40 pptv at ∼40 km, decrease concentration with altitude that is considerably slower than predicted by current models. This could be an indication atmospheric source as yet unidentified.

During three missions in 1992, 1993, and 1994, the Millimeter‐wave Atmospheric Sounder (MAS) measured volume mixing ratio profiles of stratospheric chlorine monoxide (ClO) at 204 GHz from space shuttle. Owing to shuttle orbit, measurements were restricted tropical midlatitudes. We compared zonal mean correlative ClO by an airborne 649 radiometer, a ground‐based 278 instrument on Mauna Kea, Hawaii, Version 4 Microwave Limb (MLS) Upper Atmosphere Research Satellite (UARS). The agreement...

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Aircraft Sounding Testbed, or NAST, has been developed and deployed on the NASA ER-2 high-altitude aircraft. testbed consists of two colocated scanning instruments: a Fourier-transform interferometer spectrometer (NAST-I) with spectral coverage 3.7-15.5 /spl mu/m, passive microwave (NAST-M) channels near oxygen absorption lines at 50-57 GHz 118.75 GHz. provides first coregistered imagery from high-resolution...

Abstract. We present a re-analysis of upper stratospheric ClO measurements from the ground-based millimeter-wave instrument January 1992 to February 2012. These are made as part Network for Detection Atmospheric Composition Change (NDACC) Mauna Kea, Hawaii, (19.8° N, 204.5° E). Here, we use daytime and nighttime together form day-night spectrum, which difference in day night profiles is retrieved. results then compared UARS Aura Microwave Limb Sounder (MLS) instruments. also compare them our...