The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
F. Hasebe - One of the best experts on this subject based on the ideXlab platform.
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Cold Trap dehydration in the tropical tropopause layer characterised by sower chilled mirror hygrometer network data in the tropical pacific
Atmospheric Chemistry and Physics, 2012Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, Yoichi Inai, H Vomel, Shinya Ogino, Takashi Shibata, Suginori Iwasaki, Ninong KomalaAbstract:Abstract. A network of balloon-borne radiosonde observations employing chilled-mirror hygrometers for water and electrochemical concentration cells for ozone has been operated since the late 1990s in the Tropical Pacific to capture the evolution of dehydration of air parcels advected quasi-horizontally in the Tropical Tropopause Layer (TTL). The analysis of this dataset is made on isentropes taking advantage of the conservative properties of tracers moving adiabatically. The existence of ice particles is diagnosed by lidars simultaneously operated with sonde flights. Characteristics of the TTL dehydration are presented on the basis of individual soundings and statistical features. Supersaturations close to 80% in relative humidity with respect to ice (RHice) have been observed in subvisible cirrus clouds located near the Cold point tropopause at extremely low temperatures around 180 K. Although further observational evidence is needed to confirm the credibility of such high values of RHice, the evolution of TTL dehydration is evident from the data in isentropic scatter plots between the sonde-observed mixing ratio (OMR) and the minimum saturation mixing ratio (SMRmin) along the back trajectories associated with the observed air mass. Supersaturation exceeding the critical value of homogeneous ice nucleation (OMR > 1.6 × SMRmin) is frequently observed on the 360 and 365 K surfaces indicating that Cold Trap dehydration is in progress in the TTL. The near correspondence between the two (OMR ~ SMRmin) at 380 K on the other hand implies that this surface is not sufficiently Cold for the advected air parcels to be dehydrated. Above 380 K, Cold Trap dehydration would scarcely function while some moistening occurs before the air parcels reach the lowermost stratosphere at around 400 K where OMR is generally smaller than SMRmin.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
Atmospheric Chemistry and Physics Discussions, 2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 S, 107.60 E) and Tarawa, Kiribati (1.35 N, 172.91 E) in December 2003 to examine the efficiency of the "Cold Trap'' dehydration in the tropical tropopause layer (TTL). Trajectory analysis based on bundles of trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels are supposed to follow, for interpreting the water vapor concentrations observed by radiosondes in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that dry air parcels are exposed to low temperatures while humid air parcels do not experience Cold conditions during advection, in support of the "Cold Trap'' hypothesis. It is suggested that the observed air parcel retained the water vapor by roughly twice as much as the minimum saturation mixing ratio after its passage through the "Cold Trap,'' although appreciable uncertainties remain.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Abstract Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 ◦ S,107.60 ◦ E) and Tarawa, Kiribati (1.35 ◦ N, 172.91 ◦ E) in December 2003 to examine theefficiencyofthe“ColdTrap”dehydrationinthetropicaltropopauselayer(TTL).Trajectory 5 analysis based on bundles of trajectories suggest that the modification of air parcels’identity due to irreversible mixing by the branching-out and merging-in of nearby tra-jectories is found to be an important factor, in addition to the routes air parcels aresupposed to follow, for interpreting the water vapor concentrations observed by ra-diosondes in the TTL. Clear correspondence between the observed water vapor con- 10 centration and the estimated temperature history of air parcels is found showing thatdry air parcels are exposed to low temperatures while humid air parcels do not expe-rience Cold conditions during advection, in support of the “Cold Trap” hypothesis. It issuggested that the observed air parcel retained the water vapor by roughly twice asmuch as the minimum saturation mixing ratio after its passage through the “Cold Trap,”
Anna Scrugli - One of the best experts on this subject based on the ideXlab platform.
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Development and Evaluation of a Thermoelectric Cold Trap for the Gas Chromatographic Analysis of Atmospheric Compounds
Analytical Chemistry, 1998Co-Authors: Michael W. Holdren, Scott N. Danhof, Grassi Michael J, Stets Joseph A, Bill Keigley, Victor Woodruff, Anna ScrugliAbstract:A prototype of a thermoelectric Cold Trap system has been designed, built, and evaluated. The unit is used to preconcentrate trace volatile organic compounds prior to analysis. The thermoelectric Cold Trap unit provides an alternative to the normally used liquid nitrogen-cooled Traps as a means to preconcentrate sampled components. The thermoelectric system is especially applicable in field monitoring programs, where logistical burdens are often encountered when supplying large amounts of liquid cryogens. Likewise, one does not have to be concerned with the expense and downtime associated with the use of liquid cryogens. The thermoelectric Cold Trap assembly can be easily interfaced with any chromatographic system using a two-position six-port valve. The operating principle is based upon the normal sample adsorption/desorption cycle and GC analysis. The Cold Trap system includes a custom-designed Cold Trap module (commercially available thermoelectric module components have been used), an adsorbent tube h...
N. Komala - One of the best experts on this subject based on the ideXlab platform.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
Atmospheric Chemistry and Physics Discussions, 2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 S, 107.60 E) and Tarawa, Kiribati (1.35 N, 172.91 E) in December 2003 to examine the efficiency of the "Cold Trap'' dehydration in the tropical tropopause layer (TTL). Trajectory analysis based on bundles of trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels are supposed to follow, for interpreting the water vapor concentrations observed by radiosondes in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that dry air parcels are exposed to low temperatures while humid air parcels do not experience Cold conditions during advection, in support of the "Cold Trap'' hypothesis. It is suggested that the observed air parcel retained the water vapor by roughly twice as much as the minimum saturation mixing ratio after its passage through the "Cold Trap,'' although appreciable uncertainties remain.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Abstract Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 ◦ S,107.60 ◦ E) and Tarawa, Kiribati (1.35 ◦ N, 172.91 ◦ E) in December 2003 to examine theefficiencyofthe“ColdTrap”dehydrationinthetropicaltropopauselayer(TTL).Trajectory 5 analysis based on bundles of trajectories suggest that the modification of air parcels’identity due to irreversible mixing by the branching-out and merging-in of nearby tra-jectories is found to be an important factor, in addition to the routes air parcels aresupposed to follow, for interpreting the water vapor concentrations observed by ra-diosondes in the TTL. Clear correspondence between the observed water vapor con- 10 centration and the estimated temperature history of air parcels is found showing thatdry air parcels are exposed to low temperatures while humid air parcels do not expe-rience Cold conditions during advection, in support of the “Cold Trap” hypothesis. It issuggested that the observed air parcel retained the water vapor by roughly twice asmuch as the minimum saturation mixing ratio after its passage through the “Cold Trap,”
M. Fujiwara - One of the best experts on this subject based on the ideXlab platform.
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Cold Trap dehydration in the tropical tropopause layer characterised by sower chilled mirror hygrometer network data in the tropical pacific
Atmospheric Chemistry and Physics, 2012Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, Yoichi Inai, H Vomel, Shinya Ogino, Takashi Shibata, Suginori Iwasaki, Ninong KomalaAbstract:Abstract. A network of balloon-borne radiosonde observations employing chilled-mirror hygrometers for water and electrochemical concentration cells for ozone has been operated since the late 1990s in the Tropical Pacific to capture the evolution of dehydration of air parcels advected quasi-horizontally in the Tropical Tropopause Layer (TTL). The analysis of this dataset is made on isentropes taking advantage of the conservative properties of tracers moving adiabatically. The existence of ice particles is diagnosed by lidars simultaneously operated with sonde flights. Characteristics of the TTL dehydration are presented on the basis of individual soundings and statistical features. Supersaturations close to 80% in relative humidity with respect to ice (RHice) have been observed in subvisible cirrus clouds located near the Cold point tropopause at extremely low temperatures around 180 K. Although further observational evidence is needed to confirm the credibility of such high values of RHice, the evolution of TTL dehydration is evident from the data in isentropic scatter plots between the sonde-observed mixing ratio (OMR) and the minimum saturation mixing ratio (SMRmin) along the back trajectories associated with the observed air mass. Supersaturation exceeding the critical value of homogeneous ice nucleation (OMR > 1.6 × SMRmin) is frequently observed on the 360 and 365 K surfaces indicating that Cold Trap dehydration is in progress in the TTL. The near correspondence between the two (OMR ~ SMRmin) at 380 K on the other hand implies that this surface is not sufficiently Cold for the advected air parcels to be dehydrated. Above 380 K, Cold Trap dehydration would scarcely function while some moistening occurs before the air parcels reach the lowermost stratosphere at around 400 K where OMR is generally smaller than SMRmin.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
Atmospheric Chemistry and Physics Discussions, 2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 S, 107.60 E) and Tarawa, Kiribati (1.35 N, 172.91 E) in December 2003 to examine the efficiency of the "Cold Trap'' dehydration in the tropical tropopause layer (TTL). Trajectory analysis based on bundles of trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels are supposed to follow, for interpreting the water vapor concentrations observed by radiosondes in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that dry air parcels are exposed to low temperatures while humid air parcels do not experience Cold conditions during advection, in support of the "Cold Trap'' hypothesis. It is suggested that the observed air parcel retained the water vapor by roughly twice as much as the minimum saturation mixing ratio after its passage through the "Cold Trap,'' although appreciable uncertainties remain.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Abstract Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 ◦ S,107.60 ◦ E) and Tarawa, Kiribati (1.35 ◦ N, 172.91 ◦ E) in December 2003 to examine theefficiencyofthe“ColdTrap”dehydrationinthetropicaltropopauselayer(TTL).Trajectory 5 analysis based on bundles of trajectories suggest that the modification of air parcels’identity due to irreversible mixing by the branching-out and merging-in of nearby tra-jectories is found to be an important factor, in addition to the routes air parcels aresupposed to follow, for interpreting the water vapor concentrations observed by ra-diosondes in the TTL. Clear correspondence between the observed water vapor con- 10 centration and the estimated temperature history of air parcels is found showing thatdry air parcels are exposed to low temperatures while humid air parcels do not expe-rience Cold conditions during advection, in support of the “Cold Trap” hypothesis. It issuggested that the observed air parcel retained the water vapor by roughly twice asmuch as the minimum saturation mixing ratio after its passage through the “Cold Trap,”
M. Shiotani - One of the best experts on this subject based on the ideXlab platform.
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Cold Trap dehydration in the tropical tropopause layer characterised by sower chilled mirror hygrometer network data in the tropical pacific
Atmospheric Chemistry and Physics, 2012Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, Yoichi Inai, H Vomel, Shinya Ogino, Takashi Shibata, Suginori Iwasaki, Ninong KomalaAbstract:Abstract. A network of balloon-borne radiosonde observations employing chilled-mirror hygrometers for water and electrochemical concentration cells for ozone has been operated since the late 1990s in the Tropical Pacific to capture the evolution of dehydration of air parcels advected quasi-horizontally in the Tropical Tropopause Layer (TTL). The analysis of this dataset is made on isentropes taking advantage of the conservative properties of tracers moving adiabatically. The existence of ice particles is diagnosed by lidars simultaneously operated with sonde flights. Characteristics of the TTL dehydration are presented on the basis of individual soundings and statistical features. Supersaturations close to 80% in relative humidity with respect to ice (RHice) have been observed in subvisible cirrus clouds located near the Cold point tropopause at extremely low temperatures around 180 K. Although further observational evidence is needed to confirm the credibility of such high values of RHice, the evolution of TTL dehydration is evident from the data in isentropic scatter plots between the sonde-observed mixing ratio (OMR) and the minimum saturation mixing ratio (SMRmin) along the back trajectories associated with the observed air mass. Supersaturation exceeding the critical value of homogeneous ice nucleation (OMR > 1.6 × SMRmin) is frequently observed on the 360 and 365 K surfaces indicating that Cold Trap dehydration is in progress in the TTL. The near correspondence between the two (OMR ~ SMRmin) at 380 K on the other hand implies that this surface is not sufficiently Cold for the advected air parcels to be dehydrated. Above 380 K, Cold Trap dehydration would scarcely function while some moistening occurs before the air parcels reach the lowermost stratosphere at around 400 K where OMR is generally smaller than SMRmin.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
Atmospheric Chemistry and Physics Discussions, 2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 S, 107.60 E) and Tarawa, Kiribati (1.35 N, 172.91 E) in December 2003 to examine the efficiency of the "Cold Trap'' dehydration in the tropical tropopause layer (TTL). Trajectory analysis based on bundles of trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels are supposed to follow, for interpreting the water vapor concentrations observed by radiosondes in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that dry air parcels are exposed to low temperatures while humid air parcels do not experience Cold conditions during advection, in support of the "Cold Trap'' hypothesis. It is suggested that the observed air parcel retained the water vapor by roughly twice as much as the minimum saturation mixing ratio after its passage through the "Cold Trap,'' although appreciable uncertainties remain.
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In situ observations of "Cold Trap" dehydration in the western tropical Pacific
2006Co-Authors: F. Hasebe, M. Fujiwara, N. Nishi, M. Shiotani, H. Vömel, S. Oltmans, H. Takashima, S. Saraspriya, N. KomalaAbstract:Abstract Water vapor sonde observations were conducted at Bandung, Indonesia (6.90 ◦ S,107.60 ◦ E) and Tarawa, Kiribati (1.35 ◦ N, 172.91 ◦ E) in December 2003 to examine theefficiencyofthe“ColdTrap”dehydrationinthetropicaltropopauselayer(TTL).Trajectory 5 analysis based on bundles of trajectories suggest that the modification of air parcels’identity due to irreversible mixing by the branching-out and merging-in of nearby tra-jectories is found to be an important factor, in addition to the routes air parcels aresupposed to follow, for interpreting the water vapor concentrations observed by ra-diosondes in the TTL. Clear correspondence between the observed water vapor con- 10 centration and the estimated temperature history of air parcels is found showing thatdry air parcels are exposed to low temperatures while humid air parcels do not expe-rience Cold conditions during advection, in support of the “Cold Trap” hypothesis. It issuggested that the observed air parcel retained the water vapor by roughly twice asmuch as the minimum saturation mixing ratio after its passage through the “Cold Trap,”