GCSS WG3 REPORT AND RECOMMENDATIONS
WORKSHOP, NOVEMBER 1-3, 1995
NASA Goddard Institute for Space Studies
EXECUTIVE SUMMARY
The second workshop of GCSS Working Group 3 was held at the NASA Institute for Space Studies on November 1-3, 1995. The objective of the workshop was to better understand the role of extra-tropical layer clouds on climate and to further our progress towards their proper incorporation within climate models. There were 24 presentations made at the workshop, several discussions were held, and a number of action items were identified.
The workshop was comprised of several themes. This included detailed observations from cloud radars and aircraft, high resolution simulations of several cases, the generation of large scale impacts from these simulations, the use of column models, the use of ISCCP information, the results of climate model simulations of extra-tropical layer clouds, and upcoming field experiments of interest to the working group. Several different situations of layering from different regions of the world were discussed in particular. This included oceanic, coastal and continental situations; precipitation ranged from very heavy rainfall to very light snow.
It was felt that there are several key scientific areas that need to be addressed in regards to these cloud systems. Work needs to be carried out on assessing whether frontal-scale circulation parameterizations may be needed, the structure and impacts of layering needs to be improved, the water budgets of the systems need to be better simulated, and orographic effects need to be better handled.
A number of actions for the next year were agreed upon. To relate as directly as possible to climate model parameterization improvements, comprehensive datasets from several cases will be established, large scale calculations from high resolution simulations will be expanded, current microphysical parameterizations will be assessed, column models will be used more rigorously, and ISCCP information will be used more effectively for specific cases. To advance the overall understanding of the critical aspects of extra-tropical layer clouds, greater use will be made of cloud profiling radars to determine layering, studies will be conducted of the occurrence of supercooled liquid layers, the concept of precipitation efficiency will be improved, and a plan for orographic effects will be established.
Support was also given to upcoming field experiments that should provide major contributions to the working group's efforts. This includes SALPEX(New Zealand), FASTEX (North Atlantic), and GCIP (central U.S.). These efforts should provide us with unprecedented information over the next couple of years on extra-tropical layer systems to support further parameterization developments.
In summary, the workshop was extremely successful. It surpassed its scientific objectives and it also brought together a very diverse group of researchers to jointly develop a comprehensive program.
1. INTRODUCTION
There were 24 presentations made during the workshop. These were organized into those concerned with observations (mainly layering), cloud system modeling and the use of satellite information, column models, and global climate models.
A brief summary of these sections is presented in Section 2 and an overview of resulting recommendations and actions is presented in Sections 3-4. Preliminary plans for the 1996 workshop are show in Section 5 and a timeline of working group activities is shown in Section 6.
The workshop has clearly established that this working group is taking a global perspective. Major contributions are being made by individuals or groups working in their own areas but through the use of satellite data, global weather centre products and through a common approach, everyone is also contributing to and is an essential component of the overall global effort.
2. BRIEF SUMMARY OF PRESENTATIONS AND ENSUING DISCUSSIONS
2.1 LAYERING
2.1.1 Introduction
The presentations were mainly concerned with the geometrical nature, the cloud microphysical composition, and the thermodynamic structure of cloud systems. Information was obtained using several observational tools including radar, radiometers, aircraft, lidars and dropsondes.
Modelers need to ensure that they are reproducing realistic atmospheric phenomena for the right reasons. This requires that cloud layering be accounted for properly.
2.1.2 Current Knowledge
It is clear that cloud structures are extremely complex, and there are now many data sets from different field experiments which document important characteristics of these clouds. However, much as a climatology of cloud characteristics is needed, it clearly is not available now, nor is it likely to be in the near future. However, existing data sets can be coordinated, and episodic, single site measurements can be normalized in ways to give them greater physical significance. (For instance expressing cloud boundary heights as a function of the tropopause height). Existing data sets have a great deal of useful information which are likely to contribute a significant improvement in model parameterizations if used judiciously. At the same time it is not yet entirely clear how important layering is, or the kind of resolutions that are necessary to have useful layering data.
2.1.3 Requirements for Information on Layering
In planning future field work and coordinating efforts between modelers and observationalists, it is imperative to pick a well defined, but limited number of hypotheses to drive experimental design. The set of hypotheses is not the same for different kinds of models, and a individual set needs to be generated for single column models, mesoscale models, and GCMs respectively. This approach would address the important issue of what parameters are important (and to what vertical and horizontal scales) and is intended to focus preliminary investigations and collaborations. It is understood and agreed that an understanding of processes is essential to the generation of models which model realistic atmospheric processes. A draft list of hypotheses and requirements for respective model types needs to be developed. The model types are: cloud resolving models, mesoscale models, global climate models, and column version of global climate models.
This set of working hypothesis clearly needs to be accompanied by a set of "bridge" hypothesis which will serve to interconnect the models operating at different scales.
It is also critical to clearly establish how important layering is to large scale models. Different approaches are being used for accounting for layering; it may be that some averaging approach is suitable for climate model purposes but this needs to be determined.
2.1.4 Overview of Needed Actions
Given the growing body of cloud data being collected by radar and supporting instrumentation, and in anticipation of the 5 radars which will soon be on line and operating continuously at DOE/ARM CART sites, it may be advantageous to the GEWEX program to establish a centralized radar data archive similar to that established for lidars by ECLIPS. Two kinds of archives would be useful: the first would be catalogs of information from vertically pointing radar data for entire field experiments which could be used to generate statistics. A second kind of archive could gather comprehensive multi-sensor data sets for specific case studies. The latter kind of archive should somehow be clearly stratified by synoptic situation, however it is not clear exactly what form this classification scheme would take. Any kind of archive which involves several different organizations, especially across international borders will have certain political and logistical difficulties.
It is important that observationalists and modelers collaborate, however it is not clear how to initiate productive relationships in this area. Is it in the interests of the GEWEX program to initiate exchange programs? Even as modelers need to incorporate observational data into their work, observationalists need to utilize models to provide physical explanations for their observations. Also, it may be useful for modelers to begin producing clearly observable quantities such as radar reflectivities, which do not have the ambiguities associated with derived parameters, such as particle sizes and/or concentrations which are derived from radar reflectivities.
It is clear that the global coverage of surface measurements needs to be expanded, particularly to the tropics, Arctic and unobserved midlatitude sites so that meaningful intercomparisons can be achieved. The single site measurements are not useful unless they are within the context of a more universal interpretation.
2.1.5 Specific Actions
Several actions are suggested to allow for the proper handling of layer cloud features within appropriate models. These include:
It is critical to try and further document the occurrence and characteristics of layers. This can be done from a global perspective to gain a better appreciation of the nature of the problem. In terms of the cloud system approach being followed by GCSS, a focus on the layering and its relation to specific systems is needed as well.
Given the varying nature of the models needed for achieving our objective, it must be realized that different working hypothesis need to be applied to each. Doug Johnson will take the lead to develop these hypotheses and to communicate these to the group.
It is critical at the same time to begin to improve the necessary parameterizations from observations. This will be comprised of several components including the determination of what observations are needed and communicating this information to others. This will be led by Doug Johnson. To begin this process, it is also necessary to start producing observational relationships from existing datasets that could be useful for modelers. This will to begin with focus on the datasets from only a few groups but as experience is gained this will be expanded (Uttal ,Moss, Mace).
As much of the results of these actions as possible will be made available to the rest of the community. As appropriate, this can take advantage of the group's home page.
2.2 CLOUD SYSTEM MODELLING
2.2.1 Summary of Presentations
There were a number of presentations made on the simulation of extra-tropical layer systems in different regions of the world (Tables 1 and 2). There were also some preliminary results presented on the large scale effects of these systems. In tandem, work on the application of satellite information to these cases in particular was shown. Based upon these presentations, a number of summarizing points can be made and a number of suggested actions arose from ensuing discussions.
There was a wide variety of extra-tropical layering cases chosen for study. The cases were from southern Australia, New Zealand, the US Rockies, the east coast of Canada, the Arctic Ocean, the eastern Atlantic, northern Germany, and the North Sea. The focus in most of the cases was on extra-tropical frontal systems, although the two US Rockies cases (Colorado upslope case and the precipitation over the Rockies) were largely generated by anticyclonic systems in interaction with topography. The cases varied in their evolution. Rapid evolution occurred in the Canadian East Coast case in particular, whereas the northern Canadian case was probably the most steady state. None of these was atypical of the region and so they form a very good basis for studies aimed at assessing their representation within climate models. A summary of the basic properties of the systems will need to be prepared for inclusion on the home page.
From a collective point of view, the situations also reflect a number of different situations such as: flat surface (over ocean, sea ice and land), orography (Rockies, Southern Alps, Baltic Region), frontal forcing (varying from very weak to very strong), and varying sub-cloud conditions (from very dry to very moist).
A number of state-of-the-art simulations of extra-tropical layer clouds have been performed. Several models were used in these calculations. These were: DARLAM (Australia), MM5 (US), RAMS (US and NZ), MC2 (Canada), Szeto-Cho (Canada), Unified (UK), REMO (Germany), and GESIMA (North Sea). More information on these models will be added to our home page in the future.
The cases are also unique in the sense that some of them represent excellent testbeds for the examination of particular processes. This includes different phases of particles (Canadian East Coast, US upslope, Scotland multi-layer), the role of sublimation or evaporation (Arctic, Australia and eastern Atlantic cases), as well as ice nucleation and timing (US upslope case). From an examination of the cases collectively, it is expected that we will eventually make substantial progress on the scaling of frontal circulations and on the efficiency of precipitation production.
Several of the cases (both US cases, Germany case, New Zealand case) will also allow us to gain a better appreciation of the role of topography on these systems and as testbeds for dealing with sub-grid orography within climate models.
Some initial attempts (by the upslope Rockies, the eastern Atlantic, the Australian, and the northern Canadian cases) have been made to estimate the larger scale parameters from these high resolution simulations. There was no consensus on the overall implications of these results, other that in all cases there was a major impact on the large scales. There was some concern that the large scale effects will be quite depend upon the location within the storm in which the calculations were made.
From the satellite perspective, a hierarchy of critical issues was shown. Areal coverage, mean microphysical properties, cloud top and base, optical thickness, and particle size distributions were some the main elements. Many of these critical elements are being determined through ISCCP.
GISS analysis of sounding information for layering in relation to individual systems was very enlightening and could be very useful for synthesizing for radar and in-situ measurements.
A key question for the model efforts was raised: is there some scale above which there is little confidence in GCMs ability to replicate the essential elements that are needed?
2.2.2. Action Items
Several action items arose as a result of the discussions of the cloud system model simulations. These included:
. A brief summary of the different cases that have been prepared needs to be assembled. This will mention as appropriate the "typical" nature of these systems. As part of this, develop a grid of features of different aspects of their attributes.
. Specifically point out the role that the different cases are filling in the overall strategy of the WG.
. Modify the large scale calculation requirements in light of suggestions for more surface and geography. In addition, there is a critical need to establish a workable, consistent definition of precipitation efficiency.
. No specific action plan for orographic situations was proposed at the workshop even though this is a critical element to several of the situations. It may be that this could work with other initiatives such as the GEWEX Hydrometeorology Panel (GHP) to examine the effect of orography on precipitation within regional energy and water cycle experiments.
. A very specific issue was mentioned in the discussion that needs clarification. Under some conditions, a thin layer of liquid cloud remains on top of layered clouds even when the temperature is well below freezing. This can have an important radiative effect but there is little knowledge as to whether this is a common feature. This group will set about trying to address this issue.
. Be sure that all the cases are identified on our home page with a summary of the situation and the key findings, including those for which presently there are no plans to continue the analysis. Some of these can be re-visited.
. For those planning to continue the analysis of their cases, there must be a commitment to enter a full collaborative GCSS WG3 effort. This extends to those who may not be able to directly carry out the simulations. with others for a joint GCSS WG3 initiative to develop the best possible simulations for the purpose of improving GCM representation.
. For those above, must decide on how data is to be organized for sharing purposes. This must address the needed data formats and the structure of the archives. It is suggested that model data every 6 h would represent a reasonable starting point.
. Keep the community up-to-date on progress through continual updating of home page, etc. of model and interpretation results. We need to get away from the concept that progress is mainly reported at our annual workshops. Technology is allowing much better communication that we should take advantage of.
. Consider the possible addition of ECMWF and NMC re-analysis information to the datasets on the specific cases. This would represent another means through which all the datasets are linked and may in the future be one means of providing initialization information during intercomparison experiments. It should be added that either in the current re-analysis effort or in future ones, good relations with these groups could results in our enhanced datasets being better assimilated.
2.3 COLUMN MODELS AND LARGE SCALE DIAGNOSTICS
2.3.1 Summary
The problems of using CRM outputs to provide initialization, forcing and validation data to GCM column models (CMs) was discussed at the workshop. Without proper knowledge on the scaling between the variables on the CRM grid scale and variables on the GCM grid scale, the best one can do is to relate the grid box mean variables in the CRM to the grid-scale variables of the CM. However, it has also been pointed out that higher-moment statistics of the CRM grid-scale variables will be useful in the deduction of physically-based parameterizations of cloud processes. As for the forcing of CMs with CRM outputs, it is generally agreed that to maintain strict physical consistency within the CM, only the horizontal advective tendency terms should be used to force the CMs. It was also been suggested that some bulk cloud effects obtained from the CRM might be included in the forcing to reduce the degrees of freedom (i.e. to isolate out some specific cloud processes) in the cloud scheme during the development of the prototype scheme.
2.3.2 Recommendations and Actions
It was suggested that several items be added to the large scale diagnostic calculations. This includes grid-point values of temperature, velocities and water substances within a columnar sub-domain at 20 min intervals. Ideally, data from several columns covering various parts of the simulated cloud systems storms should be archived. In addition, the mean horizontal advective tendency terms and divergence of the eddy correlation, terms for prognostic variables of the CM (e.g. temperature, water vapor, cloud water, and vertical velocity.
An assessment of the relative magnitudes of various large-scale effects of mid- and high latitude layer cloud systems by using CRM outputs is needed. This is a critical element of our overall GCSS goal and participating scientists in the different regions should be encouraged to complete the analysis of their simulated cases in this regard. It is expected that major progress on this issue will have been achieved by autumn, 1996 with some of the groups finishing earlier. As appropriate, results should be communicated through the home page.
It was suggested that the initial testing of the column model approach will utilize the 2D simulations of the Canadian Arctic case and would use the Sundqvist scheme to start with. It is expected that major progress on this will be completed by April, 1996 and will be led by Kit Szeto and input from others is expected. Progress will be reported through the home page.
In tandem, preliminary preparations will be started for applying the column techniques to other cases from around the world. One element of this will be to reach a consensus of the formats of the CRM output needed for the calculations. This latter aspect should be completed by April, 1996.
2.4 GLOBAL CLIMATE MODELS
2.4.1 Summary
All the global climate model groups recognize that they need to improve their representation of clouds. Each of the presentations at the workshop showed some of the impacts resulting from recent improvements in their models.
It was noted that there doesn't seem to have been enough effort devoted towards extra-tropical layer cloud studies of GCM performance. Other regions such as the Tropics have received far more attention.
Extra-tropical cloud systems are a major source for moisture in the upper troposphere. They may in fact have a larger role in this process than convection. However, it appears that this cycling by extra-tropical layer cloud systems is not handled properly in some climate models which as too dry in the high troposphere during the winter.
It also appears that the mid-latitude kinetic energy is not simulated well by climate models. Results suggest that the models underpredict the actual values.
By putting in a physically-based parameterization of an ice scheme into the Max Plancke model, the occurrence of mixed phase clouds was reduced substantially. However, there is little information to assess what the actual situation is.
Increasing the fall-out rate of ice within the Hadley Centre model significantly altered the mid-latitude cloud cover and resulted in widespread depletion of ice above 50 KPa.
Global climate models have major problems in their radiative balance in the extra-tropical region. It is difficult to precisely determine the magnitude of this effect however. The probable cause of this effect is extratropical layer clouds. An attempt to quantify the effects is being undertaken by NASA Goddard by producing maps and histograms of cloud optical depth/PC and comparing these with ISCCP results.
Traditionally, there has been relatively little attention placed on the examination of individual extra-tropical systems with climate models. The effort has been focused on longer-term averages.
From the global climate model community, the challenge for the cloud system modelling group is to show that through the computation of large scale effects that they can capture the essential features of the systems. If this is realized, then the global climate modelers will be more than willing to adopt the results of these realizations to improve their physics packages. This can be rephrased somewhat to state that the critical question for the cloud system modelers is to asses the scales to which global climate models must move in order to account for the needed impacts of these systems.
2.4.2 Recommendations and Actions
Presently available information on these clouds needs to be better used for assessing the ability of climate models to replicate their critical features. The greater use of ISCCP information is one example of this; comparison studies with cloud profiling radar measurements is another. The comparison of GCM results against ISCCP results become more of a "standard" benchmark within the working group.
More attention needs to be paid to snapshot analyses of GCM output as opposed to long-term average results. This should help to assess model capabilities of simulating actual mid-latitude cloud systems.
Continued communication is needed between the climate model community and those involved in smaller-scale studies. This in practice should also involved joint efforts to assess climate model, performance.
There is a need for more information on concentrations and sizes of ice particles, as well as more information on liquid water and its temperature variation.
2.5 UPCOMING EXPERIMENTS
Summary presentations were made on 3 upcoming activities. FASTEX is a large international experiment taking place over the north Atlantic during January and February, 1997. It has a wide variety of observational platforms and the ensuing information from this experiment will be very beneficial to later working group activities.
SALPEX will be occurring in November, 1996 over the southern Alps of New Zealand. The focus is on the heavy rain situations that can lead to flooding episodes. This is an excellent situation for studying orographic influences of oceanic cloud systems.
The GCIP regional water and energy cycle experiment is looking to enhance its atmospheric component. The first major opportunity to do this is in connection with northern activities starting in the winter of 1997/98. At this time, the area is affected mainly by extra-tropical layer clouds that need to be well-simulated to handle their precipitation and radiation impacts.
3. OVERVIEW OF RECOMMENDATIONS
The successful realization of the goal of this working group requires the support of the agencies supporting the participating scientists.
To enhance this commitment, it is recommended in particular that:
. Climate modelling centres should view this GCSS initiative as a positive contribution to their mandate and should allow some of their scientists to participate in our activities.
. An effort be maintained to fully appreciate the large scale impacts of mountain upslope conditions since these situations also provide some of the best information of slantwise ascent and ice nucleation.
. Global climate modelling centres are encouraged to pay more attention to the analysis of the time evolution of individual cloud systems.
4. OVERVIEW OF ACTIONS
The workshop identified a number of specific actions that need to be addressed. These are summarized here.
. An overview of the microphysical parameterizations required by the different model types will be established and an action plan for assessing appropriate observations for developing these will be established. This work will be completed by autumn, 1996 and will be led by Doug Johnson.
. The occurrence, nature and impacts of layering will be better defined using the cloud sensing radar now (or soon to be)available. As appropriate, this information will start to be analyzed from global and system relative frames of reference. Ongoing progress is to be made available to the group through appropriate correspondence including our home page and major progress is expected by autumn, 1996 and will be led by Taniel Uttal and Gerald Mace.
. The large scale requirements from cloud system models will be amended in light of suggestions made at the workshop. This will involve more information on the water cycling by the systems, and the need for more surface information. The information will be added to the WG3 home page. It is expected that the validation of the large scale effects will include radiative properties, budgets and precipitation efficiencies. This is to be accomplished by Kit Szeto and is expected to be completed by January, 1996.
. A consistent definition of precipitation efficiency will be developed. This is one measure of the requirements from climate models to simulate the critical features of the systems. This effort will draw upon past efforts in regards to this parameter and investigations of systems in different regions will be asked to determine this parameter. The dialogue on this issue, as well as the final definition, will be handled in large part through our home page. It is expected that this effort will be completed by August, 1996. The effort will be led by Brian Ryan.
. A discussion of the unique aspects of all the chosen cases will be made available to all participants. A global map showing the locations of these systems will be produced as part of this initiative. It is expected that this documentation will be completed by January, 1996 and will be led by Ron Stewart.
. The cloud system calculations for several cases will continue. As these simulations are completed, the attention will shift towards the large scale calculations. At the next workshop, the full large scale effects of all the simulated cases should be presented.
. A strategy for making meaningful calculations of orographically affected systems needs to be established. A first action in this regard is that Brian Gaudet will ask David Randall to summarize the means that this situation is currently handled within global climate models. This summary should be completed by January, 1996 and will be posted on our home page to solicit suggestions for further actions in light of our need to account for these systems.
. To allow for open exchange of relevant information, a procedure for doing this will need to be established. To begin with, a procedure for interacting with ISCCP will be needed. This may also include a request that potential vorticity be one of the variables made available for each of the efforts. Standardization of the data archive formats for cloud system models is also urgently needed. Draft ideas will be posted on our home. This will be led by Ron Stewart and George Tselioudis.
. The use of column models to bridge the gap between cloud system models and global climate models will be pursued. This critical step is a major part of our GCSS strategy and so we need to be starting the process now of gaining experience in this effort. Simple calculations will first be done largely using the 2d results from the Beaufort Sea case. All progress will be reported to the group as a whole through updates on the home page. A progress report will be made at the 1996 workshop. This effort will be led by Kit Szeto and Lubomir Levkov.
5. 1996 WORKSHOP
The objectives of this workshop will build on our ongoing efforts. It is expected that particular focus will be paid to:
. layering and microphysical parameterizations
. occurrence of liquid layers
. large scale impacts from different regions
. precipitation efficiency and climate simulations
. strategy for orographic systems
. preparations for cloud system model intercomparisons
. column model progress and assessments of climate model assumptions
. representation of cloud systems by climate models.
. if appropriate, preliminary impacts of our work on climate models.
The location and timing of the next workshop has not yet been decided. It will probably be in the October period in Europe. Specific suggestions should be made to Ron Stewart. A decision should be made by February, 1996.
6. TIMELINE 1995 Nov 10 Draft WG3 report on home page Dec 1 Add section for latest large scale calculations Dec 1 Draft of data exchange procedures on home page Dec 15 Summary of workshop presented at GCSS meeting 1996 Jan Completion of workshop report Mar Review article on climate impact issues completed Oct/Nov Workshop #3 Nov Review article started on large scale results Nov SALPEX experiment over New Zealand 1997 Jan FASTEX over eastern Atlantic Ocean
Table 1: EXTRA-TROPICAL LAYER CLOUD SYSTEM SIMULATIONS
LOCATION STUDY SITUATION OROGRAPHY/STAGE/ MODEL CONTACT
EFFICIENCY
Australia CFRP Cool Change N/M/L DARLAM B Ryan
New Zealand SALPEX Heavy Rain Y/M/? RAMS M Revell
Colorado WISP Upslope Snow Y/M/? MM5 R Rasmussen
Rockies - Heavy Snow Y/?/? RAMS B Gaudet
Atlantic Canada CASP II Deepen. Storm N/E/? MC2 A Tremblay
Arctic Canada BASE Warm Front N/M/L-H Szeto-Cho K Szeto
East Atlantic FRONTS Storm systems N/M/? Unified S Ballard
Germany BALTEX Frontal system N/M/? REMO B Rockel
North Sea EUCREX Occlusion N/M/? GESIMA L Levkov
1 Orographic effects (Yes or No)/ Mature or Evolving Systems/
Precipitation Efficiency (Low or High)
Table 2: FUNDAMENTAL PROCESSES IN DIFFERENT SITUATIONS Sub-Cloud Diabatic Heat CFRP, BASE Embedded Convection SALPEX Frontogenesis BASE, CASP II, FRONTS92, CFRP, BALTEX Microphysical nucleation WISP evaporation/ sublimation BASE, CFRP multi-phases CASP II, WISP Layering EUCREX, BASE, WISP, FRONTS92 Radiation BASE, CFRP, BALTEX, EUCREX Rain SALPEX, FRONTS92, BALTEX Slant Ascent WISP Snow BASE, Rockies, WISP, CASP II Subgrid Orography SALPEX, WISP
APPENDIX: ABSTRACTS OF PRESENTATIONS AT WORKSHOP:
Reinking, R., T. Uttal, J. Snider, R. Kropfli, E.W. Eloranta, P. Piironen, A. Piironen, R. Bruintjes and P. Pilewski, 1995: Multi-sensor distinction of cloud properties in deep and layered clouds.
Kropfli, R.A., S.Y. Matrosov, T. Uttal. A.S. Frisch, B.E. Martner and J.B. Snider, 1995: Studies of radiatively important clouds with 8-millimeter wavelength Doppler radar.
Mace, G.G., T.P. Ackerman, B.A. Albrecht, D.M. Babb, and R.M. Peters, 1995: An examination of cirrus cloud characteristics observed by a 94 GHz Doppler cloud radar.
Hanesiak, J.M., V.R. Kezys, S. Haykin and R.E Stewart, 1995: Cloud layering observations in southern Ontario.
Clough, S.A., 1995: Layering observed by dropsoundings from IOP 1 of Fronts 92.
Moss, S.J. and D.W. Johnson, 1995: Aircraft observations of the microphysical characteristics of frontal clouds around the U.K.
Katzfey, J.J. and B.F. Ryan, 1995: Modification of the thermodynamic structure of the lower troposphere by the evaporation of precipitation ahead of a cold front: a CFRP case study.
Revell, M.J., M.R. Sinclair and D.S. Wratt, 1995: Numerical simulation of a heavy rain event over the Southern Alps of New Zealand.
Rasmussen, R., 1994: Upslope snow simulations over Coloradoduring WISP.
Gaudet, B. and W.R. Cotton, 1995: Application of new microphysics scheme to winter snowfall prediction.
Tremblay, A. and A. Glazer, 1995: Parameterization of mixed-phase layer clouds.
Szeto, K.K., J.M. Hanesiak and R.E Stewart, 1995: Moist simulation of a high latitude warm-frontal system.
Ballard, S.P. and H.W. Lean, 1995: Model representation of the structure of a developing frontal wave observed during the Fronts 92 experiment.
Levkov, L. and B. Rockel, 1995: 3D numerical simulation of clouds during the 1993 EUCREX.
Szeto, K.K., 1995: A preliminary study of the forcing of GCM column models by using CRM outputs.
Tselioudis, G., W.B. Rossow and A.D. Del Genio, 1995: A view of extra-tropical layered clouds from global observations and climate models.
Lohmann, U. and E. Roeckner, 1995: Simulation of cloud water and cloud ice in the ECHAM general circulation model.
Bushell, A. and D. Gregory, 1995: Recent results of cloud parameterization changes in the UK Meteorological Office Unified model.
Wratt, D.S., M.J. Revell and M.R. Sinclair, 1995: Cloud and precipitation research over the Southern Alps of New Zealand (SALPEX).