Atmos Composition
Modeling
Giovanni-3 Online Users Manual: 5. Services and Operations
In the nomenclature of Giovanni, a service provides a data visualization or analytical result requested by the user. Giovanni operations are steps in the data processing sequence which are performed to produce the service output.
5.1 Giovanni Analytical Services and Operations
- Animation
- Lat-Lon Area Plot, Time-averaged
- Lat-Lon Plot, Difference Map
- Latitude-Time Hovmöller Plot
- Longitude-Time Hovmöller Plot
- Correlation Plot
- Comparison Plot
- Cross-Map Plot (Latitude-Pressure)
- Cross-Map Plot (Longitude-Pressure)
- Cross-Map Plot (Time-Pressure)
- Scatter Plot
- Scatter Plot, Time-averaged
- Curtain Plot
- Time Series, Area-averaged
- Time Series Difference
- Time Series, Area Statistics
- Vertical Profile
- Zonal Mean
In the table below, the data lineage appears below the description of the analytical service. Each step in the data lineage is an operation performed by Giovanni to create the output from the analytical service. Each step is linked to an Operation Technical Summary page that describes this operation in more detail.
Some important operations may be included in several different services (and thus will appear in the visualization lineage) when invoked by user preference: these types of operations are also included in the table. The Parameter Masking operation is sometimes invoked by user preference and sometimes invoked by mandatory settings in Giovanni; because it may not appear in a given lineage, it only appears in the Operations table.
Below the first table is a table listing the SERFs in the Global Change Master Directory (GCMD) and the corresponding Operation Technical Summary for each of the Giovanni-3 operations.
| Analytical Service | Description |
|---|---|
| Animation | The Animation output option creates a series of monthly area plots for the selected region and displays them sequentially. This option is useful for rapidly visualizing regions with seasonal variability and determining the most illustrative months for area plot output. Operation steps performed to generate this visualization: |
| Anomaly | The Anomaly operation calculates the parameter anomaly for a selected time-period, based on the parameter climatology. Anomaly values can be displayed as lat-lon maps or time-series. Anomalies are useful for determining large differences from normal or "mean" conditions. The anomaly operation can only be requested when a parameter climatology is available. 1. [Anomaly] |
| Lat-Lon Area Plot, Time-averaged | To generate a time-averaged area plot, the data values for each grid cell (which may also be called a pixel) in the user-specified area are averaged over the user-specified time range. The average value of the data parameter for each grid cell is plotted and displayed. Parameter weighting or pixel weighting may be used to produce the plot. Parameter weighting is used for the Aerosol Small Mode Fraction. Operation steps performed to generate this visualization: |
| Lat-Lon Plot, Difference Map | This service creates an area plot of the difference between two parameters or two different data sets of the same parameter. The latter function is useful for generating anomalies utilizing data parameter climatologies. Operation steps performed to generate this visualization: |
Latitude vs. time and longitude vs. time Hovmöller plots are plots of the selected parameter as either longitudinal variation versus time (latiitude-averaged) or latitudinal variation versus time (longitude-average). These plots allow a two-dimensional representation of changes occurring in a given region spanning a selected time period. Operation steps performed to generate this visualization: | |
| Correlation Plot | This service creates a plot of the correlation coefficient for two parameters over a specified time period. Operation steps performed to generate this visualization: |
| Comparison Plot | This service creates an area plot with two parameters. The values of the first parameter are represented with a color palette, and the values of the second parameter are represented with labeled contour lines overlaid on the color plot of the first parameter. Operation steps performed to generate this visualization: |
This service creates atwo-dimensionalrepresentation of data parameter values plotted in pressure or altitude (in the vertical dimension) vs. latitude or longitude (in the horizontal dimension). The data parameter values in the Cross-Section Plot are interpolated and displayed in log-scale.
Operation steps performed to generate this visualization: 1. [Data Fetching] ... 2. [Grid Subset] ... 3. [Time Avg] ... 4. [Dimension Avg] ... 5. [Cross Section and Vertical Profile Rendering] | |
| Cross-Map Plot (Time-Pressure) | This service creates a two-dimensional representation of data parameter values plotted in pressure or altitude (in the vertical dimension) vs. time (in the horizontal dimension). The data parameter values in the Cross-Section Plot are interpolated and displayed in log-scale.
Operation steps performed to generate this visualization: 1. [Data Fetching] ... 2. [Grid Subset] ... 3. [Dimension Avg] ... 4. [Cross Section and Vertical Profile Rendering] |
A scatter plot is a two-dimensional (X-Y) plot of two selected parameters. The user specifies the time range, and each grid cell (pixel) provides one average X value and one average Y value calculated over this time range. The X and Y values are plotted and a least squares line is fitted to the distribution. Operation steps performed to generate this visualization: Scatter Plot: Scatter Plot, Time-Averaged: | |
| Curtain Plot | This service creates a two-dimensional representation of data parameter values plotted against pressure or altitude (in the vertical dimension) and distance along the satellite ground track (in the horizontal dimension). The data parameter values in the Curtain Plot are displayed using a color palette. Operation steps performed to generate this visualization: (documentation of these steps is currently in progress) 1.[Data Fetching] ... 2. [Swath Pressure] ... 3. [Swath Stitch] ... |
| Time Series, Area-averaged | The area-averaged time-series service calculates a single average data parameter value for the entire user-specified area for each time element in the user-specified time range. Each average value is plotted against the time units to create the time-series output.Parameter weighting or pixel weighting may be used to produce the plot. Parameter weighting is used for the Aerosol Small Mode Fraction. This time-series service should be utilized for multi-parameter overlay plots. Operation steps performed to generate this visualization: |
| Time-Series Difference | This service creates a time-series plot of the difference between two parameters at each time step in a specified time period. One application of this service is for examining anomalies, computed by generating the differences of a parameter during a specific time period in comparisoin to mean values calculated over a much longer time period (climatologies). Operation steps performed to generate this visualization: |
| Time-Series, Area Statistics | This operation generates statistics to accompany a time-series plot. The statistics included are the weighted mean, pixel count, weighted standard deviation, maximum, and minimum. This service is recommended for single parameter analysis. Operation steps performed to generate this visualization: |
| Regridding | The regridding operation (g3Regrid) has been implemented for services which require datasets with the same resolution. This step will be especially useful for data intercomparison services (such as Correlation Maps, Lat-Lon map of time averaged differences, etc.) where the data are provided by different instruments. Because the regridding step will only appear in the lineage when it is invoked by the user, it is given a separate description here. 1. [Regridding] |
| Vertical Profile | The Vertical Profile operation displays the nearest vertical profiles to a selected pointfor agiven date. The vertical profiles are displayed as an X-Y plot, with the X-axis as the geophysical value and the Y-axis as altitude in pressure units. Users may display from 1 to 6 profiles (the default is 3) along with error bars. Each vertical profile is represented by its own color. Operation steps performed to generate this visualization: 1. [Data Fetching] ... 2. [Swath Stitch] ... |
| Zonal Mean | The Zonal Mean over a given area is the sequence of data generated by taking the average over a range of longitudes for each latitude. The Zonal Mean calculation only works with data in a single atmospheric layer (defined by pressure in hPA), such as 300 hPA as an example. The zonal mean cannot be calculated for a pressure range, i.e., for the range 300-400 hPA.
Operation steps performed to generate this visualization: (documentation of these steps is currently in progress) 1. [Data Fetching]... 2. [Grid Subset]... 3. [Time Avg]... 4. [Dimension Avg]... 6. Zonal Mean |
5.2 Giovanni-3 Operations
The Global Change Master Directory (GCMD) contains SERFs (Service Entry Resource Format) summarizing each of the Giovanni operations. They are linked in the table below. The third column provides a link to the corresponding Operation Technical Summary.
G3 appears in these names for consistency, as they were created for Giovanni during the Giovanni-3 development and implementation stage. [More information]
