From email@example.com Wed Jul 17 10:39:54 1996 Date: Fri, 05 Jul 1996 10:48:41 -0700 (PDT) From: "Dr. Barry Huebert"
To: ACE-1 List Subject: Workgroup report for Lagrangians LAGRANGIAN EXPERIMENTS -B. Huebert, 7/4/96 This group assessed the status of dynamics and chemistry data for Lagrangians A and B, then discussed the ways various groups plan to make use of this data. We identified several papers that people hope to produce. Dynamical data and analyses The analysis of the chemical data depends heavily on understanding the dynamical contexts of the Lagrangian experiments. Several of these analyses, including the calculation of turbulent fluxes, are already completed. Many will appear soon on Qing Wang's home page. A group including Lenschow, Wang, Siems, Businger, and Austin has agreed to prepare two Lagrangian overview papers, similar to what Bretherton produced for ASTEX/MAGE. One would cover the synoptic setting, satellite observations, BL evolution, trajectories, divergence, and the tracking balloons. The other paper will address smaller-scale phenomena including micrometeorology, entrainment, details of mixing, and cloud processes. This nicely-coordinated group plans to have much of that information ready within a few months. In addition to those two papers, Businger and Siems each plan papers comparing their trajectory analyses to the balloon trajectories. Lenschow plans to evaluate the utility of circular patterns for flux, divergence, and entrainment measurements. Russell plans a paper on the information which aerosol microphysical evolution can contribute to understanding BL mixing processes. Jim Moore has agreed to do a paper on the pre-Lagrangian B flight (#23), and what it can tell us about the source of the air and aerosols we followed for the next three flights. Lagrangian B appears to be a very interesting case dynamically, since the tagged air moved from warmer to colder water, in contrast to ASTEX/MAGE and most other evolutionary observations. Wang's initial flux analyses suggest that there was a strong capping inversion at 1400 m during at least flights 24 and 25, which may have prevented any entrainment of FT air. There was virtually no heat flux, so shear dominated the mixing. The Richardson number may be a particularly useful parameter in this situation. While the freedom from entrainment may seem desirable for understanding chemical changes, it was necessarily accompanied by increasing stability of the surface layer, so that noticeable gradients of such species as peroxide were evident. Aerosol chemistry and microphysics also suggest a weak inversion at 500m on these flights. It may be that we cannot use a simple box-model chemical budget approach in this situation due to stable stratification near the surface, and will have to rely on more complex dynamical/chemical models to solve for surface fluxes and chemical conversion rates. Chemical and microphysical data Most of the chemical and microphysical data will be ready for evaluation in the October/November time-frame. Many PI's indicated they will password-protect their data, with the intention of giving the password to virtually anyone who requests it. The intention seems to be that data providers can then have a conversation with potential data users prior to the use of their data. Status: NH3 was not measured on every Lag flight, due to crew-duty limitations. Numbers may be ready by October. NO was done on all Lag flights, and should be ready by August. SO2 and DMS data processing will not resume until October. No Drexel rep attended the workshop, but we hope for Lagrangian data by the end of the year. McMurry's data will be cleaned up by August. Russell has half of the flights done, but wants to look for droplet shatter in her data. It isn't obvious, as it is in some other data sets. Anderson will have completed the microscopic evaluations of the Lagrangians by mid-August Clarke's non-OPC data will be ready in a few months. Eisele's analysis is done, but a final version is not yet ready. Much of Kok's data is done and submitted to the archive. Blake's data is ready. A first draft of Huebert's inorganic impactor data is now in the database. The external sampler was inoperative on Lag B; Lag A data will be submitted by August. The CIT organic filter data may be ready by December, but not in time for AGU. Hudson's CCN spectrometer did not operate on a Friday flight. The remaining flights are being edited now, and should be in the archive in two months. No one knows the status of Valero's TDDR data. The lidar data will be submitted soon, and may be put into a book of images for visual inspection. It will be range-corrected, but not analyzed for layers. Lynn Russell agreed to work with Krista Laursen to learn a relatively complex layer-detecting algorithm, but will only run it on the Lagrangian flights. According to Don Lenschow, it is not a straightforward thing for numerous individuals to run. We need to find a computer-facile individual who will run this algorithm for at least the other flights on which we did Lenschow circles. Some RAF data is being redone. There is quite a lot of concern that we have no reliable data on aircraft altitude, since the radar altimeters were not functional. The pressure-altitude algorithm that RAF routinely applies does not even use airport pressure corrections, so that the altitudes of several flight legs in the present database imply that we flew underwater! Huebert has discussed this issue with Allen Schanot, and we will try to find a suitable way of providing more realistic altitude information, perhaps by using GPS or the lidar to calibrate PALT in each study area. Apparently Krista Laursen is applying attitude corrections to RAF's radiometer data, so that we will have actual upwelling and downwelling radiances in a later version of the dataset. Quite a bit of surface and seawater data from the ships is ready now. This includes DMS and NH3 concentrations and fluxes from Disco. Southern Surveyor data should be ready in two months. Lagrangian analyses Many people expressed desires to use the Lagrangian data. These include: Huebert and many others want to examine the evolution of sulfur chemistry. Davis wants to run a moving-box model. Suhre wants to use a moving-column model, which includes vertical exchange, on H2O2, ozone, and DMS. Huebert wants to evaluate the validity of the Lagrangian observational strategy. To what extent did we study homogeneous airmasses and how well can we represent their chemistry and dynamics with this approach? Wang, Siems, and others want to study BL evolution. Numerous aerosol dynamics modelers (including Russell, Raes, Majeed) want to run models including coagulation, growth, and other microphysical processes. Huebert and Quinn are interested in NH3 fluxes. Blake and others want to look at budgets of organohalides, hydrocarbons, and ozone. (Blake's HC analysis may be more a seasonal investigation than one confined to the Lagrangians.) Russell wants to use the chemical and microphysical data to constrain BL dynamics. Huebert and others want to compare surface fluxes inferred from BL evolution with those derived from surface measurements. It appears that these two sets of Lagrangian observations will be used for testing and improving a wide variety of chemical, microphysical, and dynamical models. ------------------------------------------------------------------------ From firstname.lastname@example.org Wed Jul 17 10:40:03 1996 Date: Fri, 05 Jul 1996 22:44:12 -1000 (HST) From: Tony Clarke To: "Dr. Barry Huebert" Cc: ACE-1 List Subject: Re: Workgroup reports for C-130 and Lagrangians Barry; A small correction to your C-130 report. Actually it is not true that nobody knows the status of the TDDR data (Valero, Bucholtz). As I reported at the meeting and indicated in my "Radiative closure" report, most of the TDDR data apears to be good and it is the expectation of Anthony Bucholtz to have this data in the data set by September. They have been busy on other field campaigns since ACE-1. Also my CN and UCN counter data should be ready in a few weeks. This will consist of files edited for shatter and files with shatter included so that others might evaluate their data (eg. Lynn Russell). Our DMA and OPC data should be out before AGU. Tony