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Premium member Presentation Transcript Surface Inversions, Atmospheric Stability, and Spray Drift: Surface Inversions, Atmospheric Stability, and Spray DriftSurface Temperature Inversions:: Surface Temperature Inversions: Are very common Are easy to recognize Affect the dispersal of very small spray droplets suspended in the air Do not increase the amount of off-site movement Can increase the potential for offsite affects & the distance at which affects can be observedAtmospheric Stability: Atmospheric Stability Inversions cause STABLE atmospheric conditions The concept of atmospheric stability helps understand how inversions affect drift Close to the ground, atmospheric stability changes regularly between STABLE, NEUTRAL, & UNSTABLE Slide4: The large scale trend in the atmosphere is that temperature decreases with height 55 F 60 F 65 F 70 F 75 F 80 F Slide5: Where there is a decrease in temperature with height greater than the adiabatic rate the atmosphere is UNSTABLE 55 F 60 F 65 F 70 F 75 F 80 F Slide6: When the atmosphere is UNSTABLE air parcels near the surface will rise and expand because they are warmer & less dense than the air above 55 F 60 F 65 F 70 F 75 F 80 F Droplets or particles suspended in the air will be dispersed/dilutedSlide7: Cloud of 5-25 u oil droplets generated under unstable conditions 105 foot temperature monitoring tower 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°FSlide8: 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°F 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°FSlide9: A temperature inversion is an area where temperature increases with height. 65 o F 60 o F 55 o F 50 o F 45 o F 40 o F It can begin at the ground.Slide10: A temperature inversion is an area where temperature increases with height, this is area is the inversion layer 30 o F 40 o F 50 o F 60 o F 70 o F 80 o F 55 50°F 48°F 46°F 44°F 42°F 40°F 38°F 40°F 42°F 44°F 46°F 48°F Or it can begin above the ground. These aloft inversions will be discussed at the end of the program Slide11: When temperature increases with height the atmosphere is STABLE. 65o F 60o F 55o F 50o F 45o F 40o F Vertical mixing of the air and dispersion of small droplets is suppressed.Slide12: A parcel of air near the surface is always cooler & more dense than the air above, so it can’t rise and disperse. 65o F 60o F 55o F 50o F 45o F 40o F If forced down by a current of air, it will immediately rise back. Slide13: 65o F 60o F 55o F 50o F 45o F 40o F If forced up by a current of air, it will immediately sink back. Slide14: The parcel of air can’t rise and disperse, but it can be move laterally in the light variable winds typical of a surface inversion 65o F 60o F 55o F 50o F 45o F 44o F Slide15: 105’ 35°F 64’ 30°F 32’ 29°F 16’ 28°F 8’ 26°F Temperature Profile Surface Inversion - STABLE CONDITIONS Wind 0.6 mphSlide16: Temperature Profile Surface Inversion - STABLE CONDITIONS 105’ 35°F 64’ 30°F 32’ 29°F 16’ 28°F 8’ 26°FSlide17: 8’ 27°F 16’ 29°F 32’ 31°F 64’ 32°F 105’ 33°F Surface Inversion - STABLE CONDITIONSSlide18: 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature Profile Surface Inversion - STABLE CONDITIONS Cold air drainage down a slopeSlide19: 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature Profile Surface Inversion - STABLE CONDITIONS Cold air drainage down slopeSlide20: A Surface Inversion can extend upwards 5, 50, 100, 500 ft or more. 65o F 60o F 55 F 50o F 45o F 40o F Height (of the inversion) doesn’t matter: If the application is made within the inversion it, the effects will be similar.Slide21: 8’ 26°F 16’ 28°F 32’ 29°F 64’ 30°F 105’ 35°F Surface inversion extending above the tower Layering observed when oil droplets released at ground level or top of tower. Clouds moving in different directions.Slide22: 8’ 33°F 16’ 36°F 32’ 37°F 64’ 38°F 105’ 38°F .5 mph wind 2.5 mph wind Shallow surface inversion STABLE conditions up to 64’ NEUTRAL conditions at 105’ Cloud is dispersingSlide23: Surface Inversions are part of the daily cycle unless wind or cloud cover intervene 55 F 60 F 65 F 70 F 75 F 80 F Slide24: During the night, unless clouds or wind intervene, the ground loses heat cooling the air above. Slide25: Unless wind intervenes the surface inversion will continue until the sun begins to heats the groundSlide26: During the day when cloud cover is light, the sun heats the ground warming the air above. This causes in unstable conditions unless wind intervenes.Slide27: As the sun sets the ground begins to lose more heat than it gains, cooling the air above. In the absence of heavy cloud cover and/or wind a surface inversion will begin to form.Slide28: 8’ temperature 105’ temperature 16’ temperature 32’temperature 64’ temperature Solar energySlide29: Inversion - Stable Unstable Inversion - Stable Sunrise Sunset Daily Cycle 11/9/93 Daily Cycle 11/9/93How to recognize a surface inversion: How to recognize a surface inversion Sunset to just after sunrise Windless to low wind conditions (<2-3 mph) Clear to partly cloudy skies Ground fog (if sufficient humidity exists) Dust hanging over a roadway Smoke from a chimney forming a layer Dew or frost (if sufficient humidity exists)Slide31: Signs of a surface inversion in the early morning Windless or light variable wind Ground Fog Frost (or dew) Lack of heavy cloud coverSlide32: Smoke from a chimney forming a layer Surface inversion - early morningHow to recognize the potential for a surface inversion: How to recognize the potential for a surface inversion Sun is getting low in the sky Wind is becoming light and variable Clear to partly cloudy skies Surface Inversions don’t:: Surface Inversions don’t: Increase the amount of spray droplets moving off-siteSurface Inversions can:: Surface Inversions can: Decrease the dispersion of droplets too small to quickly settle out. Result in a higher air concentration of these small droplets. Increase the potential for off-target effects. Increase the distance at which off-target effects can be observed. Increase the size of the area affected. Cause the direction of drift to be unpredictableReducing the effects of Surface Inversions on Spray Drift: Reducing the effects of Surface Inversions on Spray Drift Minimizing production of very small drops Using equipment the minimizes the number of small drops suspended in the air Morning applications are likely to have shorter exposure to STABLE conditions than evening applicationsSlide37: When the atmospheric stability is NEUTRAL, there is little or change in temperature with height. Low heavy cloud cover and/or wind contribute to NEUTRAL conditions. 80 o F 80 o F 80 o F 80 o F 80 o F 80 o F Vertical mixing is not suppressed as under STABLE conditions, and the turbulence of even a 5 mph wind is effective in dispersing suspended small droplets.Slide38: 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile NEUTRAL CONDITIONS Wind 4.5 mphSlide39: 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile NEUTRAL CONDITIONS Wind 4.5 mphSlide40: Surface Inversion No wind Neutral Conditions 4.5 mph wind 7:00 AM 8:30 AM 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature ProfileNeutral conditions can be the best time to spray: Neutral conditions can be the best time to spray Wind direction if often consistent Good dispersion of droplets too small to quickly settle out. Aloft Inversions: A temperature inversion is an area where temperature increases with height, this is area is the inversion layer 30 o F 40 o F 50 o F 60 o F 70 o F 80 o F 55 50°F 48°F 46°F 44°F 42°F 40°F 38°F 40°F 42°F 44°F 46°F 48°F Aloft Inversions Are not likely to effect applications to agricultural crops Low altitude aloft inversions can affect aerial forestry application Low altitude aloft inversions are often surface inversions in the process of dissipating & are therefore short livedSurface Temperature Inversions:: Surface Temperature Inversions: Are very common Are easy to recognize Affect the dispersal of very small spray droplets suspended in the air Do not increase the amount of off-site movement Can increase the potential for offsite affects & the distance at which affects can be observed You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
ramsey Manlio Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 95 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: February 25, 2008 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Surface Inversions, Atmospheric Stability, and Spray Drift: Surface Inversions, Atmospheric Stability, and Spray DriftSurface Temperature Inversions:: Surface Temperature Inversions: Are very common Are easy to recognize Affect the dispersal of very small spray droplets suspended in the air Do not increase the amount of off-site movement Can increase the potential for offsite affects & the distance at which affects can be observedAtmospheric Stability: Atmospheric Stability Inversions cause STABLE atmospheric conditions The concept of atmospheric stability helps understand how inversions affect drift Close to the ground, atmospheric stability changes regularly between STABLE, NEUTRAL, & UNSTABLE Slide4: The large scale trend in the atmosphere is that temperature decreases with height 55 F 60 F 65 F 70 F 75 F 80 F Slide5: Where there is a decrease in temperature with height greater than the adiabatic rate the atmosphere is UNSTABLE 55 F 60 F 65 F 70 F 75 F 80 F Slide6: When the atmosphere is UNSTABLE air parcels near the surface will rise and expand because they are warmer & less dense than the air above 55 F 60 F 65 F 70 F 75 F 80 F Droplets or particles suspended in the air will be dispersed/dilutedSlide7: Cloud of 5-25 u oil droplets generated under unstable conditions 105 foot temperature monitoring tower 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°FSlide8: 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°F 8’ 41°F 16’ 41°F 32’ 40°F 64’ 40°F 105’ 38°FSlide9: A temperature inversion is an area where temperature increases with height. 65 o F 60 o F 55 o F 50 o F 45 o F 40 o F It can begin at the ground.Slide10: A temperature inversion is an area where temperature increases with height, this is area is the inversion layer 30 o F 40 o F 50 o F 60 o F 70 o F 80 o F 55 50°F 48°F 46°F 44°F 42°F 40°F 38°F 40°F 42°F 44°F 46°F 48°F Or it can begin above the ground. These aloft inversions will be discussed at the end of the program Slide11: When temperature increases with height the atmosphere is STABLE. 65o F 60o F 55o F 50o F 45o F 40o F Vertical mixing of the air and dispersion of small droplets is suppressed.Slide12: A parcel of air near the surface is always cooler & more dense than the air above, so it can’t rise and disperse. 65o F 60o F 55o F 50o F 45o F 40o F If forced down by a current of air, it will immediately rise back. Slide13: 65o F 60o F 55o F 50o F 45o F 40o F If forced up by a current of air, it will immediately sink back. Slide14: The parcel of air can’t rise and disperse, but it can be move laterally in the light variable winds typical of a surface inversion 65o F 60o F 55o F 50o F 45o F 44o F Slide15: 105’ 35°F 64’ 30°F 32’ 29°F 16’ 28°F 8’ 26°F Temperature Profile Surface Inversion - STABLE CONDITIONS Wind 0.6 mphSlide16: Temperature Profile Surface Inversion - STABLE CONDITIONS 105’ 35°F 64’ 30°F 32’ 29°F 16’ 28°F 8’ 26°FSlide17: 8’ 27°F 16’ 29°F 32’ 31°F 64’ 32°F 105’ 33°F Surface Inversion - STABLE CONDITIONSSlide18: 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature Profile Surface Inversion - STABLE CONDITIONS Cold air drainage down a slopeSlide19: 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature Profile Surface Inversion - STABLE CONDITIONS Cold air drainage down slopeSlide20: A Surface Inversion can extend upwards 5, 50, 100, 500 ft or more. 65o F 60o F 55 F 50o F 45o F 40o F Height (of the inversion) doesn’t matter: If the application is made within the inversion it, the effects will be similar.Slide21: 8’ 26°F 16’ 28°F 32’ 29°F 64’ 30°F 105’ 35°F Surface inversion extending above the tower Layering observed when oil droplets released at ground level or top of tower. Clouds moving in different directions.Slide22: 8’ 33°F 16’ 36°F 32’ 37°F 64’ 38°F 105’ 38°F .5 mph wind 2.5 mph wind Shallow surface inversion STABLE conditions up to 64’ NEUTRAL conditions at 105’ Cloud is dispersingSlide23: Surface Inversions are part of the daily cycle unless wind or cloud cover intervene 55 F 60 F 65 F 70 F 75 F 80 F Slide24: During the night, unless clouds or wind intervene, the ground loses heat cooling the air above. Slide25: Unless wind intervenes the surface inversion will continue until the sun begins to heats the groundSlide26: During the day when cloud cover is light, the sun heats the ground warming the air above. This causes in unstable conditions unless wind intervenes.Slide27: As the sun sets the ground begins to lose more heat than it gains, cooling the air above. In the absence of heavy cloud cover and/or wind a surface inversion will begin to form.Slide28: 8’ temperature 105’ temperature 16’ temperature 32’temperature 64’ temperature Solar energySlide29: Inversion - Stable Unstable Inversion - Stable Sunrise Sunset Daily Cycle 11/9/93 Daily Cycle 11/9/93How to recognize a surface inversion: How to recognize a surface inversion Sunset to just after sunrise Windless to low wind conditions (<2-3 mph) Clear to partly cloudy skies Ground fog (if sufficient humidity exists) Dust hanging over a roadway Smoke from a chimney forming a layer Dew or frost (if sufficient humidity exists)Slide31: Signs of a surface inversion in the early morning Windless or light variable wind Ground Fog Frost (or dew) Lack of heavy cloud coverSlide32: Smoke from a chimney forming a layer Surface inversion - early morningHow to recognize the potential for a surface inversion: How to recognize the potential for a surface inversion Sun is getting low in the sky Wind is becoming light and variable Clear to partly cloudy skies Surface Inversions don’t:: Surface Inversions don’t: Increase the amount of spray droplets moving off-siteSurface Inversions can:: Surface Inversions can: Decrease the dispersion of droplets too small to quickly settle out. Result in a higher air concentration of these small droplets. Increase the potential for off-target effects. Increase the distance at which off-target effects can be observed. Increase the size of the area affected. Cause the direction of drift to be unpredictableReducing the effects of Surface Inversions on Spray Drift: Reducing the effects of Surface Inversions on Spray Drift Minimizing production of very small drops Using equipment the minimizes the number of small drops suspended in the air Morning applications are likely to have shorter exposure to STABLE conditions than evening applicationsSlide37: When the atmospheric stability is NEUTRAL, there is little or change in temperature with height. Low heavy cloud cover and/or wind contribute to NEUTRAL conditions. 80 o F 80 o F 80 o F 80 o F 80 o F 80 o F Vertical mixing is not suppressed as under STABLE conditions, and the turbulence of even a 5 mph wind is effective in dispersing suspended small droplets.Slide38: 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile NEUTRAL CONDITIONS Wind 4.5 mphSlide39: 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile NEUTRAL CONDITIONS Wind 4.5 mphSlide40: Surface Inversion No wind Neutral Conditions 4.5 mph wind 7:00 AM 8:30 AM 105’ 32°F 64’ 33°F 32’ 33°F 16’ 33°F 8’ 32°F Temperature Profile 105’ 43°F 64’ 36°F 32’ 32°F 16’ 30°F 8’ 28°F Temperature ProfileNeutral conditions can be the best time to spray: Neutral conditions can be the best time to spray Wind direction if often consistent Good dispersion of droplets too small to quickly settle out. Aloft Inversions: A temperature inversion is an area where temperature increases with height, this is area is the inversion layer 30 o F 40 o F 50 o F 60 o F 70 o F 80 o F 55 50°F 48°F 46°F 44°F 42°F 40°F 38°F 40°F 42°F 44°F 46°F 48°F Aloft Inversions Are not likely to effect applications to agricultural crops Low altitude aloft inversions can affect aerial forestry application Low altitude aloft inversions are often surface inversions in the process of dissipating & are therefore short livedSurface Temperature Inversions:: Surface Temperature Inversions: Are very common Are easy to recognize Affect the dispersal of very small spray droplets suspended in the air Do not increase the amount of off-site movement Can increase the potential for offsite affects & the distance at which affects can be observed