At any given moment about 4000 commercial aircraft are flying over the Earth. To an atmospheric scientist they constitute a potentially vast array of in situ measurement platforms, an obvious source of high‐resolution upper tropospheric/lower stratospheric (UT/LS) trace gas data that could not be obtained on such a continuous basis in any other way, especially over the oceans.The number of flights has been steadily growing, and the long‐term outlook for continued “funding” looks excellent given the penchant for humans to travel around the world. And yet, to date, there have been few attempts to tap this resource for atmospheric chemistry studies. One study, however, has chalked up 40 million miles over the past 5 years.

Interannual variations of tropical tropospheric temperatures are closely related to sea surface temperature (SST) changes in the tropical eastern Pacific (TEP). This study investigated the physical mechanisms for such an air-sea interrelationship. SSTs and latent heat flux were analyzed to find the unique properties of their variations during El Niño. A Gill-type model was used to investigate how a local heat source communicates with the entire tropics. Radiative fluxes in the tropics were evaluated to search for the factors limiting air temperature increases when warm SSTs remain in the TEP. We found that interannual variabilities of SST and latent heat flux are dominated by the variations in the TEP region. The SST variations there have three unique properties that allow the ocean to influence the atmosphere effectively: large magnitude, long persistence, and spatial coherence. The Gill-type model shows that a local heat source can warm the entire tropical troposphere when the heat source is near the equator. Released latent heat in the heat source region and forced adiabatic subsidence elsewhere in the tropics warm the atmosphere. As a result, a local heat source warms the entire tropical strip. The forced subsidence depresses clouds, allowing more infrared radiation to leave the atmosphere and preventing further atmospheric warming when warm SSTs remain in the TEP. This finding is verified by reanalysis data from the National Centers for Environmental Prediction.

Latitudinal distributions of NO, NOy, O-3, CO, CH3I, and H2O mixing ratios at 8.9-12 km were obtained between 30 degrees N and 10 degrees S by DC-8 aircraft measurements made in February 1994 during Pacific Exploratory Mission-West B (PEM-West B). Very low NO mixing ratios with a median value of 51 parts per trillion by volume (pptv) were observed at 9.5-12 km at 1 degrees N-14 degrees N during two flights made within 3 days. A very low median O-3 mixing ratio of 19 parts per billion by volume (ppbv) and high mixing ratios of H,O and CH,I were simultaneously observed, suggesting that the low NO, values were probably due to the convective transport of air from the tropical marine Boundary layer to this altitude. The median NOy/O-3 ratio being a factor of 2 smaller than in the air masses in the tropical marine boundary layer might suggest the possibility that the heterogeneous removal of HNO3 during convective transport further reduced NOy levels. In addition to the measurements between 9.5 and 12 km, low values of NOy and O-3 were observed between 4 and 12 km at 1 degrees N. Divergent wind fields at 200 and 1000 hPa and infrared (IR) cloud images show that there was large scale convection (>1000 km x 1000 km) in the northeast of New Guinea Island centered around 0 degrees S and 150 degrees E as part of systematic convective activity of the Intertropical Convergence Zone (ITCZ) and the South Pacific Convergence Zone (SPCZ). This type of large scale convection could have transported air with low levels of NOy and O-3 to the middle and upper troposphere over a wide area in the tropics. On the other hand, NO mixing ratios of 50-200 pptv and high NOx/NOy ratios of 0.4-0.6 were observed at 9.5 km between 4 degrees S and 10 degrees S. High H2O mixing ratios of 600-1200 parts per million by volume (ppmv) and low CO mixing ratios of 65 ppbv observed in the air mass indicated that the high NO values were probably due to NO production by lightning. Satellite observations showed relatively frequent lightning flashes over the New Guinea Island for 3 days prior to the aircraft measurements. These results are considered to be consistent with the idea that, in general, marine convection is not accompanied by lightning activity, whereas convection over land is. Because of the large areal extent of the influences from these processes, the convective transport of low NO air and NO production by lightning should play critical roles in controlling the abundance of reactive nitrogen in the equatorial region.

Carbon monoxide measurements made from the space shuttle show maxima over South America, central Africa, the eastern Mediterranean, and China. The maxima appear to be associated with either concomitant or prior convection in the air masses which carries boundary layer air into the upper troposphere. Previous aircraft measurements of carbon monoxide and ozone over South America are shown to be consistent with this view. In the tropics the three regions of long-term mean rising motion, which form part of the Walker circulation, are associated with elevated carbon monoxide.

The objective of the NASA Global Atmospheric Sampling Program (GASP) was to establish global baseline values of selected atmospheric constituents that could be used for studies of the dynamics of the sampled region as well as for modeling purposes. Instrument packages were carried on four Boeing 747 aircraft in routine commercial service: two from Pan American, one from United.Airlines and one from Qantas Airways of Australia. Geographical coverage was therefore determined by the routes of these airlines, wih the sampling altitude being in the range of 8–13 km and usually close to 200 mb. Air intakes for the instruments were just below the center line in the nose and were opened automatically on ascent through 6 km and closed on descent through that altitude. Constituent data were recorded on tape, generally every 5 minutes, together with altitude, latitude, longitude, air temperature and wind velocity, the latter obtained from the aircraft’s inertial guidance system. At a later date, tropopause heights from the analysis by the National Meteorological Center (NMC) in Washington were added to the data set.

Two possible factors, which in addition to Pacific sea surface temperatures might affect the mean temperatures of the tropical troposphere are Atlantic sea surface temperatures and volcanic aerosol. The Mt. Agung eruption in March 1963 produced a decrease of about 0.5 degrees C in the mean temperature of the tropical troposphere. The contribution of the Atlantic is not significant.

principal investigator. The behavior of global circulation patterns in both hemispheres, with special emphasis on stratospheric patterns, has been studied and noteworthy results have been obtained. (auth)

the northern polar vortex. Year-to-year variability in Antarctic sightings is most prominent in the number of late season clouds. Maximum PSC sighting probabilities in both polar regions occur in the region from 90 deg W through the Greenwich meridian to 90 deg E, where temperatures are coldest on average. Arctic sighting probabilities approach zero outside this region, but clouds have been sighted in the Antarctic at all longitudes during most months. Inferred PSC formation temperatures remain constant throughout the Arctic winter and are similar to those in early Antarctic winter. PSC formation temperatures in the Antarctic drop markedly in the 15 to 20-km region by September, a pattern consistent with the irreversible loss of HNO3 and H2O vapor in sedimenting PSC particles.

Changes in radiative heating and cooling rates due to both the near Infrared and 15μbands of CO2 are computed for changes in CO2 concentration from 320 to 600 and 1000 ppmv. An increase in CO2 concentration leads to a smaller net change at the in the troposphere, little net change at the tropopause, and increased cooling in the stratosphere. The 15μ and near infrared effects act in the same sense in the tropopause but tend to compensate in the stratosphere, although the near infrared contribution is generally small when compared with that due to the 15μ band. Possible effects of the changes on the generation of zonal available potential energy are suggested.

The vertical and horizontal fluxes of energy by large‐scale standing waves have been estimated on a monthly basis for the IQSY for the 100–10 mb region. A large upward flux into the region occurs in winter some of which passes into the atmosphere above 10 mb, where it may exceed the energy generated there by radiative processes. The meridional wave energy flux diverges from the 40°–60°N region and converges in both high and low latitudes in winter. The total energy flux convergence pattern shows that the polar night jet in the lower stratosphere in winter is a source of kinetic energy; when the jet collapses in the spring the same region turns into a strong sink and it is noted that while this was a gradual process in 1965 and occupied three months, there was a large absorption in March 1964 that dominated the energetics pattern in spring. The largest energy absorption occurs with the largest energy flux into the region, thus supporting previous suggestions that the spring warming is ultimately dependent on tropospheric events. The adiabatic approximation was used in the flux computations and the role of radiative processes in the observed events is briefly discussed.

An attempt was made to obtain ultraviolet photographs of Venus at the same time as 3.8-cm radar cross- section measurements. The photographs are reported in this article for comparison with the previously published radar data of Evans et al. (1966). There was no evident correlation ; it is necessary to achieve better resolution in space and time in the radar measurements before possible interrelationships can be ruled out.

The global ozone budget has been studied in detail by Junge and one of his conclusions was that further systematic measurements of surface ozone at a number of sites over the globe would be of great value in consideration of stratospheric-tropospheric exchange processes. Such studies could provide information about where and when stratospheric air reaches the lower troposphere; the vertical mixing in the lowest 1.5 to 2 km during the day essentially provides a short-circuit between the surface and 1.5 km. Combined with ozone sounding data such as that gathered over North America, it is not unreasonable to hope that eventually the quantity of stratospheric air passing into the troposphere can be estimated. An objection often raised to Junge's proposed network of surface ozone stations is that measurements made near a city can be contaminated with ozone produced locally by the action of sunlight on automobile and industrial exhausts. There is some direct evidence of such production in the controlled experiments of Ripperton and in the existence of high ozone values in the polluted air of a relatively unventilated city like Los Angeles. This may account for the fact that the only surface ozone measurements added to the literature sincemore » Junge's paper are apparently those from the Antarctic reported by Aldaz. Thus, the question of the feasibility of the network suggested by Junge has not really been decided. In view of our interest in the general circulation of ozone in the atmosphere and its possible use as a tracer of the vertical transfer of energy from the troposphere to the stratosphere, we decided to monitor surface ozone in the relatively well-ventilated region of Greater Boston. This note represents the gross results for a one-year period.« less

AbstractA series of high resolution robin falling‐sphere soundings covering the altitude range from 70 to 27 km have been examined in detail. Small‐scale wind variations with height are evident throughout. From profiles of the zonal wind components the apparent amplitudes and half‐wavelengths have been tabulated and summarized for 19 cases, divided into two seasons. A data‐reduction technique which imposes variable smoothing upon the initial balloon‐position data complicates the analysis, but the existence of wind fluctuations with vertical half‐wavelengths between 300 in and a few kilometres is definitely established.A linear theory which takes into account the effects of rotation and temperature lapse rate upon such motions is briefly discussed. It is shown that the vertical flux of energy associated with the motions may be an important energy source for the atmosphere above about 80 km. A firm estimate of the magnitude of the vertical energy flux requires further information about the periods and/or the horizontal scales of the observed motions.

COADS has been used in two approaches to compute global oceanic evaporation: (1) Using the bulk equation approach recommended at the INO January 1988 New Orleans workshop and (2) using a modified wind term to take account of evaporation in reported calm regions. Results have been compared with previous estimates by Hsiung (1986) based on the U.S. Navy Consolidated Data Set and with the work of Baumgartner and Reichel. To help with the problem of few reports south of 50°S the evaporation is considered in conjunction with other variables such as rainfall, river run-off, and salinity.