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Abstract
Washington, D. C., microbarograph records for 18 March 1969 reveal gravity-wave-associated pressure oscillations which appear to be directly related to upper tropospheric wave structure observed at the same time with a Wallops Island 10-cm wavelength radar. The consistency between the two sets of data provides new observational support for a hypothesis of long standing in the microbarograph community; namely, that shear instability in the upper tropospheric flow is indeed the mechanism responsible for the generation of such waves. The comparison presented here suggests that microbarograph arrays might be useful adjuncts to future radar studies of upper tropospheric wave dynamics, supplying such wave parameters as phase velocity and wavelength in favorable cases. A closer examination of the radar data pertinent to this event reveals an apparent vertical wave phase variation, permitting a very approximate and somewhat uncertain estimate of the wave-associated vertical flux of horizontal momentum, which is found to be ∼4 dyn cm−2. While approximate, this illustrative calculation yields a value several times greater than the annual average flux at temperate latitudes, and since microbarograph data show such events to be fairly common wintertime phenomena, we are tempted to infer that wave generation by shear instability in the upper tropospheric air flow and the resulting vertical momentum transport may be an important element of the global atmospheric momentum budget. More extensive and conclusive studies are obviously indicated.
Abstract
Washington, D. C., microbarograph records for 18 March 1969 reveal gravity-wave-associated pressure oscillations which appear to be directly related to upper tropospheric wave structure observed at the same time with a Wallops Island 10-cm wavelength radar. The consistency between the two sets of data provides new observational support for a hypothesis of long standing in the microbarograph community; namely, that shear instability in the upper tropospheric flow is indeed the mechanism responsible for the generation of such waves. The comparison presented here suggests that microbarograph arrays might be useful adjuncts to future radar studies of upper tropospheric wave dynamics, supplying such wave parameters as phase velocity and wavelength in favorable cases. A closer examination of the radar data pertinent to this event reveals an apparent vertical wave phase variation, permitting a very approximate and somewhat uncertain estimate of the wave-associated vertical flux of horizontal momentum, which is found to be ∼4 dyn cm−2. While approximate, this illustrative calculation yields a value several times greater than the annual average flux at temperate latitudes, and since microbarograph data show such events to be fairly common wintertime phenomena, we are tempted to infer that wave generation by shear instability in the upper tropospheric air flow and the resulting vertical momentum transport may be an important element of the global atmospheric momentum budget. More extensive and conclusive studies are obviously indicated.
In many respects, the prospects for U.S. meteorological research have never been brighter. Knowledge is advancing rapidly, as are supporting observing and information technologies. The accuracy, timeliness, and information content of forecasts are improving year by year. As a result, new and growing markets eagerly await the products of weather research, and opportunities for commercialization abound. Furthermore, no end to the progress of knowledge is in sight; there is plenty of interesting research left to do.
Other trends, however, give cause for concern. In particular, the growing value of weather services and science is straining long-established public–private and international partnerships, vital to our field. Closer to home, the meteorological community can see nascent signs of some of the same commercialization-related difficulties that now challenge biotechnology.
In fact, the biotechnology community's experience with commercialization of research teaches valuable lessons. Attention to these issues now, and appropriate early action, may help the meteorological community benefit from commercialization while avoiding similar pitfalls. This would not only serve our field well, it would also ensure that society continues to benefit from meteorological research advances in the decades to come.
In many respects, the prospects for U.S. meteorological research have never been brighter. Knowledge is advancing rapidly, as are supporting observing and information technologies. The accuracy, timeliness, and information content of forecasts are improving year by year. As a result, new and growing markets eagerly await the products of weather research, and opportunities for commercialization abound. Furthermore, no end to the progress of knowledge is in sight; there is plenty of interesting research left to do.
Other trends, however, give cause for concern. In particular, the growing value of weather services and science is straining long-established public–private and international partnerships, vital to our field. Closer to home, the meteorological community can see nascent signs of some of the same commercialization-related difficulties that now challenge biotechnology.
In fact, the biotechnology community's experience with commercialization of research teaches valuable lessons. Attention to these issues now, and appropriate early action, may help the meteorological community benefit from commercialization while avoiding similar pitfalls. This would not only serve our field well, it would also ensure that society continues to benefit from meteorological research advances in the decades to come.
Abstract
We suggest that the strata of strong echo returns frequently revealed by remote-sensor records of the stably stratified planetary bound layer (PBL) represent the wavefronts of dissipative waves (viscous and thermal-conduction waves) excited by gravity-wave encounters with the PBL and the earth's surface. The viscous waves appear to be more strongly forced and should therefore dominate the observations. This simple picture accounts for the following observed properties of the strata: 1) their nearly ubiquitous presence within the stably stratified PBL, 2) their nearly horizontal orientation, 3) the small spacing (some tens of meters, typically) separating the strata, 4) variability in that spacing in both height and time, and 5) the high shears and temperature gradients associated with the strata. Preliminary calculations of the energy fluxes and stresses associated with the wave motions, also presented here, suggest strongly that such waves are not mere curiosities of the PBL but reveal important dynamical processes. In addition, their great similarity to the sheets of temperature and current gradients in the thermocline suggests an analogous dynamical origin for the ocean phenomenon.
Abstract
We suggest that the strata of strong echo returns frequently revealed by remote-sensor records of the stably stratified planetary bound layer (PBL) represent the wavefronts of dissipative waves (viscous and thermal-conduction waves) excited by gravity-wave encounters with the PBL and the earth's surface. The viscous waves appear to be more strongly forced and should therefore dominate the observations. This simple picture accounts for the following observed properties of the strata: 1) their nearly ubiquitous presence within the stably stratified PBL, 2) their nearly horizontal orientation, 3) the small spacing (some tens of meters, typically) separating the strata, 4) variability in that spacing in both height and time, and 5) the high shears and temperature gradients associated with the strata. Preliminary calculations of the energy fluxes and stresses associated with the wave motions, also presented here, suggest strongly that such waves are not mere curiosities of the PBL but reveal important dynamical processes. In addition, their great similarity to the sheets of temperature and current gradients in the thermocline suggests an analogous dynamical origin for the ocean phenomenon.
Cleveland Abbe (1838–1916) joined the U.S. Signal Service as the government's first chief meteorologist early in 1871. An honor student in chemistry and mathematics, and a trained astronomer, Abbe brought scientific rigor and a far-reaching vision of worldwide scientific cooperation to the endeavor. He remained with the weather service until his death. During the first 30 years, he functioned as initiator and scientific watchdog in the burgeoning organization. He focused on two major scientific tasks: the optimization of the Signal Service, and the study and advocacy of theoretical meteorology. Over time he came to recognize the interconnectedness of climatology, forecasting, and physical theory. His efforts in forecasting and verification, establishing standard time, climatology, the transfer of scientific knowledge, and physical theory reveal the thrust of his professional thought. He brought all of this together in 1901. In a comprehensive scientific paper he argued against long-range weather forecasts based on empirical methodology. Instead, he proposed integration of the basic equations of physics and fluid dynamics, and laid out the mathematical means by which this might be accomplished. Just over a century later we take a new look at his work, and suggest a revised appreciation for his place in the history of meteorology.
Cleveland Abbe (1838–1916) joined the U.S. Signal Service as the government's first chief meteorologist early in 1871. An honor student in chemistry and mathematics, and a trained astronomer, Abbe brought scientific rigor and a far-reaching vision of worldwide scientific cooperation to the endeavor. He remained with the weather service until his death. During the first 30 years, he functioned as initiator and scientific watchdog in the burgeoning organization. He focused on two major scientific tasks: the optimization of the Signal Service, and the study and advocacy of theoretical meteorology. Over time he came to recognize the interconnectedness of climatology, forecasting, and physical theory. His efforts in forecasting and verification, establishing standard time, climatology, the transfer of scientific knowledge, and physical theory reveal the thrust of his professional thought. He brought all of this together in 1901. In a comprehensive scientific paper he argued against long-range weather forecasts based on empirical methodology. Instead, he proposed integration of the basic equations of physics and fluid dynamics, and laid out the mathematical means by which this might be accomplished. Just over a century later we take a new look at his work, and suggest a revised appreciation for his place in the history of meteorology.
Abstract
The NOAA Science Advisory Board appointed a task force to prepare a white paper on the use of observing system simulation experiments (OSSEs). Considering the importance and timeliness of this topic and based on this white paper, here we briefly review the use of OSSEs in the United States, discuss their values and limitations, and develop five recommendations for moving forward: national coordination of relevant research efforts, acceleration of OSSE development for Earth system models, consideration of the potential impact on OSSEs of deficiencies in the current data assimilation and prediction system, innovative and new applications of OSSEs, and extension of OSSEs to societal impacts. OSSEs can be complemented by calculations of forecast sensitivity to observations, which simultaneously evaluate the impact of different observation types in a forecast model system.
Abstract
The NOAA Science Advisory Board appointed a task force to prepare a white paper on the use of observing system simulation experiments (OSSEs). Considering the importance and timeliness of this topic and based on this white paper, here we briefly review the use of OSSEs in the United States, discuss their values and limitations, and develop five recommendations for moving forward: national coordination of relevant research efforts, acceleration of OSSE development for Earth system models, consideration of the potential impact on OSSEs of deficiencies in the current data assimilation and prediction system, innovative and new applications of OSSEs, and extension of OSSEs to societal impacts. OSSEs can be complemented by calculations of forecast sensitivity to observations, which simultaneously evaluate the impact of different observation types in a forecast model system.
