Radx2Grid Convective Stratiform - Revision history

Jcdehart: /* Separation Process */

2021-02-11T19:03:59Z

Separation Process

Jcdehart: /* Separation Process */

2021-02-11T19:03:36Z

Separation Process

Jcdehart: /* Example */

2021-02-09T23:25:02Z

Example

Jcdehart: /* Example */

2021-02-09T23:24:23Z

Example

Jcdehart: /* Separation Process */

2021-02-09T23:15:23Z

Separation Process

Jcdehart: /* Overview */

2021-02-09T23:02:55Z

Overview

Jcdehart: /* Separation Process */

2021-02-08T21:36:36Z

Separation Process

Jcdehart at 21:36, 8 February 2021

2021-02-08T21:36:00Z

Jcdehart at 21:07, 8 February 2021

2021-02-08T21:07:30Z

Jcdehart at 20:33, 8 February 2021

2021-02-08T20:33:54Z

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-The convective stratiform algorithm identifies convection in two ways:
+The convective stratiform algorithm categorizes radar echoes in two ways:
 <ol start="1" style="list-style-type: decimal;">
 <li>Intensity: high-intensity reflectivity values are also certainly found only in convective precipitation</li></ol>

← Older revision		Revision as of 19:03, 11 February 2021
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	=== '''Separation Process''' ===		=== '''Separation Process''' ===
	The default setting of Radx2Grid is to not perform the convective stratiform separation; performing the separation and saving the results to the gridded file must be enabled in the Radx2Grid parameter file (''identify_convective_stratiform_split''; line 2428).		The default setting of Radx2Grid is to not perform the convective stratiform separation; performing the separation and saving the results to the gridded file must be enabled in the Radx2Grid parameter file (''identify_convective_stratiform_split''; line 2428).
		+
		+
		+	The convective stratiform algorithm identifies convection in two ways:
		+	<ol start="1" style="list-style-type: decimal;">
		+	<li>Intensity: high-intensity reflectivity values are also certainly found only in convective precipitation</li></ol>
		+	<ol start="2" style="list-style-type: decimal;">
		+	<li>Texture: convective precipitation exhibits greater horizontal variability than stratiform precipitation</li></ol>

← Older revision		Revision as of 23:25, 9 February 2021
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	=== '''Example''' ===		=== '''Example''' ===
−	Example output from Hurricane Harvey (2017) from the Houston radar (KHGX) is shown below. In this example, the definite convective threshold was 45 dBZ, the convective radius is 5 km, the minimum texture is 15 dBZ, and the texture radius is 7 km.	+	Example output from Hurricane Harvey (2017) from the Houston radar (KHGX) is shown below. In this example, the definite convective threshold was 45 dBZ, the convective radius is 5 km, the minimum texture is 15 dBZ, and the texture radius is 7 km. Red regions indicate convective precipitation.

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 === '''Example''' ===
-An example from Taiwan is shown below.
+Example output from Hurricane Harvey (2017) from the Houston radar (KHGX) is shown below. In this example, the definite convective threshold was 45 dBZ, the convective radius is 5 km, the minimum texture is 15 dBZ, and the texture radius is 7 km.
 === '''References''' ===
 Steiner, M., Houze , R. A., Jr., & Yuter, S. E. (1995). Climatological Characterization of Three-Dimensional Storm Structure from Operational Radar and Rain Gauge Data, Journal of Applied Meteorology and Climatology, 34(9), 1978-2007. [https://doi.org/10.1175/1520-0450(1995)034%3C1978:CCOTDS%3E2.0.CO;2 Link]

@@ Line 3: / Line 3: @@
 === '''Separation Process''' ===
-The default setting of Radx2Grid is to not perform the convective stratiform separation and must be enabled in the parameter file (''identify_convective_stratiform_split''; line 2428).
+The default setting of Radx2Grid is to not perform the convective stratiform separation; performing the separation and saving the results to the gridded file must be enabled in the Radx2Grid parameter file (''identify_convective_stratiform_split''; line 2428).
-As in [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)], the first step is to identify definite convection. This process is done by flagging all points that exceed a user-defined reflectivity threshold as convective (''conv_strat_dbz_threshold_for_definite_convection''; line 2491). Note that this threshold will vary in continental and tropical convection (e.g., 53 vs 40/45 dBZ). Around each point flagged as definite convection, all points within a radius of convective influence are also flagged as convection (''conv_strat_convective_radius_km''; line 2504).
+As in [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)], the first step identifies definite convection. This process is done by flagging all points that exceed a user-defined reflectivity threshold as convective (''conv_strat_dbz_threshold_for_definite_convection''; line 2491). Note that this threshold will vary in continental and tropical convection (e.g., 53 vs 40/45 dBZ). For each point flagged as definite convection, all points within the radius of convective influence are also flagged as convection (''conv_strat_convective_radius_km''; line 2504).
-While [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)] then calculates the reflectivity difference between a point and its neighbors to identify any remaining convection, Radx2Grid instead analyzes the "texture" of the reflectivity field, which is defined as <math>\sqrt{\sigma(dBZ^2)}</math>. The texture is calculated over all points within a user-defined radius of the central point (''conv_strat_texture_radius_km''; line 2519) and is only valid if the fraction of points within the texture radius exceeds a minimum fraction (''conv_strat_min_valid_fraction_for_texture''; line 2533). All locations where the texture exceeds a user-defined threshold are also defined as convection (''conv_strat_min_texture_for_convection''; line 2547). Similar to the first step, all points within the radius of convective influence are also flagged as convection.
+While [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)] next identifies any remaining convection by calculating the reflectivity difference between a point and its neighbors, Radx2Grid instead analyzes the "texture" of the reflectivity field, which is defined as <math>\sqrt{\sigma(dBZ^2)}</math>. The texture is calculated using all points within the user-defined texture radius of the central point (''conv_strat_texture_radius_km''; line 2519) and is only valid if a sufficient fraction of the grid points within the texture radius have good data (''conv_strat_min_valid_fraction_for_texture''; line 2533). All locations where the texture exceeds a user-defined threshold are also defined as convection (''conv_strat_min_texture_for_convection''; line 2547). Similar to the first step, all points within the radius of convective influence are also flagged as convection.
+Although [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)] performs the aforementioned analysis at a single horizontal level, Radx2Grid uses a vertical layer of a user-defined depth to determine convective and stratiform precipitation (''conv_strat_min_valid_height'' and ''con_strat_max_valid_height''; lines 2452, 2464).

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 === '''Overview''' ===
-One important functionality of Radx2Grid is applying a convective stratiform separation algorithm to the gridded data. The algorithm is based on a modified version of the process described by [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)]. The separation is performed by analyzing the radar reflectivity field. The separation is important due to the distinct profiles of vertical velocity, microphysical processes, and diabatic heating in convective and stratiform precipitation. This page will describe the basic methodology and point the user to key parameters.
+One important functionality of Radx2Grid is the ability to distinguish between convective stratiform and separation precipitation in gridded radar data. The algorithm is a modified version of the process described by [http://wiki.lrose.net/index.php/Radx2Grid_Convective_Stratiform#References Steiner et al. (1995)], which analyzes the radar reflectivity field and flags grid points as convective or stratiform precipitation. Distinguishing between the two precipitation types is important due to the distinct profiles of vertical velocity, microphysical processes, and diabatic heating in convective and stratiform precipitation. This page will describe the basic methodology and point the user to key parameters.
 === '''Separation Process''' ===

← Older revision		Revision as of 21:36, 8 February 2021
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−	''Note: the algorithm is currently undergoing significant upgrades ~~and~~ will be included in a future version of LROSE, possibly in a standalone application instead of within Radx2Grid.''	+	''Note: the algorithm is currently undergoing significant upgrades that will be included in a future version of LROSE, possibly in a standalone application instead of within Radx2Grid.''
−

	=== '''Example''' ===		=== '''Example''' ===

← Older revision		Revision as of 20:33, 8 February 2021
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	=== '''Overview''' ===		=== '''Overview''' ===
	One important functionality of Radx2Grid is to apply a convective stratiform separation algorithm to gridded data. The algorithm is based on a modified version of the [Steiner et al. (1995)] algorithm.		One important functionality of Radx2Grid is to apply a convective stratiform separation algorithm to gridded data. The algorithm is based on a modified version of the [Steiner et al. (1995)] algorithm.
		+
		+
		+	=== '''Separation Process''' ===