M11-11 Turbulence Products PDF

Preview

Summary

Thomas Guinn...

Description

Aviation Turbulence

WX 301

Turbulence Guidance Products

Turbulence symbols consist of variations of upside-down “V”s

Light

Moderate

Severe

Memorize these symbols!

The AWC provides four turbulence products. 1) G-AIRMET, 2) Textual AIRMETs, 3) SIGMET, 4) Graphical Turbulence Guidance (GTG) 1.

2.

3.

4.

WAUS46 KKCI 041445 SFOT WA 041445 AIRMET TANGO UPDT 2 FOR TURB VALID UNTIL 042100 AIRMET TURB...CA AND CSTL WTRS FROM 30WSW LAS TO EED TO BZA TO 20S MZB TO 30ESE LAX TO 30WNW RZS TO 30WSW LAS

G-AIRMETS provide “point-in-time” forecasts of moderate turbulence in 3-hr intervals out to 12 hours. Updated every 3 hours.

Red (darker color): SFC-FL180 Orange (lighter color): >FL180 Also shows LLWS and high surface winds (discussed earlier)

Textual AIRMET “Tangos” provide a 6-hour “time-smeared” forecast of moderate turbulence. Updated every 6 hours.

Text AIRMET Tango Example: WAUS46 KKCI 041445 SFOT WA 041445 AIRMET TANGO UPDT 2 FOR TURB VALID UNTIL 042100 AIRMET TURB...CA AND CSTL WTRS FROM 30WSW LAS TO EED TO BZA TO 20S MZB TO 30ESE LAX TO 30WNW RZS TO 30WSW LAS MOD TURB BLW 100. CONDS CONTG BYD 21Z THRU 03Z. OTLK VALID 2100-0300Z...TURB WA OR ID MT WY NV UT BOUNDED BY 50WSW YXC-50NNW ISN-80ENE CZI-50N CHE-20ENE SLC50WSW BVL-30W BKE-30SSW YDC-50WSW YXC MOD TURB BTN FL280 AND FL400. CONDS CONTG THRU 03Z.

http://www.aviationweather.gov/adds/airmets/

Turbulence SIGMETs warn of Severe and Extreme turbulence. Valid up to four hours and only issued when necessary.

AWC Turb SIGMETs

Note: Despite being for severe or extreme turbulence, the moderate symbol is used in turbulence SIGMETs. (I have no good answer why)

Human turbulence reports are a “subjective” or “feels like” measure that depend on the pilot and aircraft. Thought Experiment: Imagine you could only measure temperature by asking a person if they “feel” hot, comfortable, or chilly Professor Dan Halperin

Grew up in Florida “It was chilly this morning”

Professor Rob Eicher

Grew up in Maryland “It was comfortable this morning”

One pilot’s severe might be another pilot’s moderate.

Eddy Dissipation Rate (EDR) is an “objective” measure of turbulence. In theory all aircraft would measure the same EDR. Thought Experiment: Imagine you could only measure temperature by asking a person if they “feel” hot, comfortable, or chilly

Professor Dan Halperin

Professor Rob Eicher

Grew up in Florida Grew up in Maryland “It was 52° this “That we can agree on. But morning” we still have better crabcakes”

Same objective temperature but each feels different to the observer.

GTG uses a weighted average of 20 common turbulence diagnostics applied to a numerical model to predict Eddy Dissipation Rate (EDR)

GTG is fully automated. Should always be used in conjunction with GAIRMET or SIGMET information.

GTG allows the user to select type of aircraft, flight level, CAT or MWT or both, and time.

GTG forecasts EDR. Severity of turbulence determined by selecting aircraft type (light, med, heavy).

Note a 25 EDR is Mod for a light aircraft.

Changing aircraft type does not change the EDR, but does change the intensity scale, because lighter aircraft would impacted more.

EDR intensity scale adjusted based on aircraft type (light, medium, heavy) EDR same, but impact changes, now 40 is Mod, and 25 light....