Term
| A hook echo radar signature is formed by what? |
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Definition
| Precipitation wrapped around the vortex. |
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Term
| Where is a hook echo usually located in relation to the parent storm? |
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Definition
| In the right rear quadrant of the parent storm with respect to its motion. |
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Term
| In what level of the storm should the radar operator look for a hook? |
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Definition
| In the lowest elevations possible. |
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Term
| The WSR–88D’s 10cm wavelength makes finding embedded thunderstorms in stratiform precipitation easier by reducing what atmospheric problem? |
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Definition
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Term
| How does the melting level appear on WSR–88D single slice reflectivity products? |
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Definition
| A ring or partial ring of enhanced reflectivity. |
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Term
| What factors may prevent detection of the melting level on WSR–88D reflectivity products? |
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Definition
| Too few clouds present at the melting level, a disruption of the melting level by some form of turbulence or convection, and heavy precipitation that may saturate the display. |
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Term
| Below what measurement of dBZs are most returns considered non-precipitable? |
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Definition
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Term
| A backward S-shaped velocity pattern suggests what type of advection is occurring? |
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Definition
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Term
| What is most likely occurring when a base velocity product displays a rapid change in velocity values over a very short distance with a directional change? |
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Definition
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Term
| The radar is to the south of a velocity pattern with inbound velocities on the left side and outbound velocities on the right side as you look at the pattern. There is a Doppler zero velocity line, oriented north-to-south, separating the inbound and outbound velocities. What does this pattern suggest? |
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Definition
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Term
| The radar is to the north of a velocity pattern with a Doppler zero line oriented west-to-east. On the north side of the zero line, closest to the radar, there are inbound velocities. On the south side of the zero line, farthest from the radar, there are outbound velocities. What does this pattern suggest? |
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Definition
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Term
| What is the best WSR–88D product to use to identify veering winds with height? |
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Definition
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Term
| What does the spectrum width product provide a display of? |
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Definition
| The variance of motions within the mean radial velocity field. |
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Term
| What can the spectrum width product be used for? |
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Definition
| It is used with other products for estimating turbulence associated with thunderstorms, frontal boundaries, and clear air. It is also used to show the validity of mean radial velocity estimates and gives a first look at possible convective development. |
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Term
| Within a sample volume, what does the WSR–88D sense? |
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Definition
| A combination of different particle motions. |
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Term
| The maximum returned power is usually at what frequency? |
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Definition
| The frequency of the backscattered energy from the largest meteorological targets. |
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Term
| In a geographical area where turbulence is suspected, what type of spectrum width values would you expect? |
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Definition
| Comparatively higher values. |
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Term
| What can the spectrum width product identify to aid in forecasting icing? |
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Definition
| The increased variance in particle velocities. |
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Term
| For which product can the spectrum width product be used as a data reliability check? |
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Definition
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Term
| How can the CR product be displayed? |
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Definition
| By itself or as a background for overlays. |
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Term
| From how many elevations does the CR product provide the WSR–88D user with a composite of reflectivity? |
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Definition
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Term
| At one geographical location, you have three elevation slices with reflectivity values of 35dBZ, 40dBZ, and 25dBZ. What reflectivity value will be displayed for that location on a composite reflectivity product? |
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Definition
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Term
| What do reflectivity values displayed on a CR product represent? |
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Definition
| The maximum reflectivity in the entire volume scan. |
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Term
| Why can volumetric overlays be used with the CR product? |
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Definition
| Because it is a volumetric product. |
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Term
| List three limitations of the CR product: |
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Definition
- Many of the typical horizontal plane signatures that do not exhibit high reflectivities are not visible on the CR product (for example, hook echo).
- Other features may also be disguised on the CR product. If you detect a classical feature on CR, investigate it further by using base reflectivity. Altitude information about the 3-D structure of reflectivity is lost.
- Since CR is made up of information that comes from the base reflectivity products, many of the same situations that affect the quality of reflectivity data also cause problems with CR. (Any three limitations will suffice)
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Term
| What is the major difference between the composite reflectivity and layered composite reflectivity maximum product? |
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Definition
| The CR product is produced by using the entire volume scan, which makes it difficult to determine the approximate altitude of a particular reflectivity value. The LRM uses three layers—low, mid, and high—in the production of the product. This allows you to look at maximum reflectivities for a specific section of the storm. |
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Term
| In how many data levels is the LRM product available? |
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Definition
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Term
| What are the data thresholds for the LRM product? |
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Definition
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Term
| What is the height range of the low layer for the LRM product? |
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Definition
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Term
| Describe a use of the LRM product: |
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Definition
| In providing the operator a quick look at significant reflectivity values for a specified layer. The LRM is an excellent way of tracking the intensity trends of strong convection. |
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Term
| Name some limitations of the LRM product: |
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Definition
- The LRM uses only three elevation angles that fall within the altitude of the layer specified; is adversely affected at distant ranges from the radar where the layer may only encompass one or two elevation slices.
- At close ranges, mid and high layer altitude products are ineffective due to the cone of silence.
- Signatures such as hook echoes, BWERs, and WERs may not be detectable because of the LRM’s use of several elevation slices.
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Term
| What is the resolution of the ULR product? |
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Definition
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Term
| List the limitations of the ULR: |
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Definition
- The ULR displays only the maximum return for the entire layer which makes it difficult to determine the location within the layer of the maximum reflectivity.
- Severe weather signatures are usually masked by higher reflectivity values being displayed over weak echo regions.
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Term
| How is the LRM APR different from the standard LRM product? |
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Definition
| An algorithm is used to remove reflectivity readings from ground targets. |
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Term
| Describe the omit all region used by the LRM APR algorithm: |
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Definition
| It is defined as the portion of the atmosphere within 45km of the RDA and below 1km in altitude. The algorithm discards all reflectivity returns from this region, thereby deleting them from the product display. |
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Term
| Describe the accept if region used by the LRM APR algorithm: |
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Definition
It is defined as the portion of the atmosphere within 103km of the RDA, on the 0.5° elevation slice and
below 3km in altitude, and not within the omit all region. A target in this region is accepted for inclusion in the product if its velocity is > 1.0m/s and its spectrum width is > 0.5m/s. |
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Term
| Describe the reject if region used by the LRM APR algorithm: |
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Definition
It is defined as the portion of the atmosphere within 203km of the RDA and below 5° in elevation. The
region does not include any of the omit all and accept if regions. A reflectivity return is rejected by the algorithm if its velocity is < 1.0 m/s and its spectrum width is < 0.5m/s. |
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Term
| What are the altitude settings for the LRM APR product? |
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Definition
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Term
| Name some of the limitations of the LRM APR product: |
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Definition
The algorithm works best if traditional clutter filtering is applied before the algorithm begins processing
data. The algorithm assumes all reflectivity returns below 1km in altitude and with 45km of the RDA to be
clutter. This could result in valid meteorological data being removed. Current parameters may not be the optimum settings and further testing may be needed to enhance the algorithms processing. |
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Term
| How many data levels does the VIL product display? |
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Definition
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Term
| The VIL product is derived from what base product(s)? |
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Definition
| The reflectivity product. |
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Term
| What is indicated by the values displayed on a VIL product? |
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Definition
| How much water is in the storm. |
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