Presentation on theme: "BAD PRESENTATION By Phillip Marzette ATMS 790 January 29, 2007 Who needs a title anyway? Now, on with the show...."— Presentation transcript:
BAD PRESENTATION By Phillip Marzette ATMS 790 January 29, 2007 Who needs a title anyway? Now, on with the show....
1996-1997 Reno Flood Michael Kaplan, Phillip Marzette and Christopher Adaniya Division of Atmospheric Sciences // Desert Research Institute // University of Nevada-Reno Background During the period of late December 1996 to early January 1997, the northern regions of Nevada and California experienced a severe flooding event. This is the first poster in a series that will explain the nature of this flood event from the global scale, to the regional scale and the mesoscale. This poster will explain how does this flood event organizes at the synoptic scale. The figures below are of infrared satellite imagery in the western Pacific Ocean and water vapor satellite imagery across the eastern Pacific Ocean from December 14, 1996 to January 1, 1997. In these figures, blue cyclone waves indicate main waves that hit the western United States and green cyclone waves indicate transient waves that get absorbed to the main cyclone wave. The elements of the first wave to hit Reno, Nevada appear in the Western Pacific about 12 days prior to the heavy rain on 00Z December 15, 1996. The first of many mid-latitude cyclone waves (CW in blue) moves off the coast of Japan. To the south, a developing mesoscale convective system (MCS) and a western Pacific tropical moisture plume (WP-TMP) are also present. 48 hours later, the moisture from CW #1 begins to interact with the moisture from the WP-TMP. There is a moisture stream emanating from the MCS that contributes to the WP-TMP. A second CW (in green) begins to move off the continent of Asia. The orange warm front symbol indicates the movement of the WP-TMP. On 00Z December 19, 1996, the first CW moves near the 180 th Meridian. A thin plume of moisture is shown between the MCS and the first cyclone wave. The first cyclone wave has its moisture content increase from the WP-TMP along the Intertropical Convergence Zone (ITCZ) back to the MCS. The second CW begins to interact with the MCS and starts to ingest tropical moisture as the CW moves to the south. This is the first image to show a cyclone wave across the eastern Pacific Ocean. On 00Z, December 21, 1996, the first cyclone makes its way to Hawaii, but the wave still remains several thousand miles west of the contiguous United States. 24 hours after the appearance of the first wave in the eastern Pacific, the MCS develops into Tropical Storm Fern. The development of this tropical storm serves to strengthen the WP-TMP. CW #2 begins to move eastward, closer to where the first cyclone wave is near Hawaii. The third CW is now visible east of the island of Hokkaido. On 00Z December 24, 1996, Tropical Storm Fern begins to strengthen east of the Philippines. Signs of the second cyclone wave strengthening from the tropics are starting to develop. CW#2 begins to get absorbed by CW #1 past Hawaii. Tropical Storm Fern is upgraded to a typhoon on 12Z December 25 1996. At the same time, the third cyclone wave begins to move past the 180 th Meridian. Another CW moves off of Japan and approaches a strong moist band from Typhoon Fern. Moving back to the eastern Pacific on the water vapor image, the first cyclone wave begins to move to the western United States on 00Z December 27, 1996. An eastern Pacific tropical moisture plume (EP-TMP) appears southwest of Mexico. The WP-TMP stretches all the way to the third cyclone in Hawaii. 12 hours later in the western Pacific, the fourth cyclone wave establishes itself near the 165 th East Meridian. This cyclone wave likely absorbs an immense amount of moisture from Typhoon Fern. At December 29, 1996 on 1130Z, Fern is downgraded to a tropical storm as the moisture from this system is merely a conveyor belt to the fourth cyclone wave. About 6 hours later, all three cyclone waves are visible in this image. The third wave is now approaching the western United States. The fourth cyclone wave is located at the 140 th west Meridian and it has the long WP-TMP from Tropical Storm Fern to feed off of. On 09Z, December 30, 1996, the fourth cyclone wave begins to draw moisture from an EP-TMP to compliment its WP-TMP. The leading edge of the warm front of CW #4 makes its way to the western United States. About 33 hours later, the WP-TMP is stretched from 15°N, 165°E to 40°N, 120°W. The brunt of the wave begins to move to the western United States. Into the new year, CW #4 arrives at the western coast of the United States. This event is where northern Nevada and California experience the most intense flooding. Part 1: Synoptic Scale Overview
1996-1997 Reno Flood Michael Kaplan, Phillip Marzette and Christopher Adaniya Division of Atmospheric Sciences // Desert Research Institute // University of Nevada-Reno Part 2: Regional Scale Overview Background This poster is the second of a series that will analyze the 1996-1997 Flood in northern Nevada and California from the synoptic scale to the meso scale. Now, we are looking at a regional time and space scale, in the order of 12 hours to a couple of days in advance. Currently, this poster takes place when the fourth cyclone wave is affecting the region (third to hit the western United States). The figures in this poster show cross sections (labeled X-SECT-in green), isentropic maps and isotachs during the heavier precipitation events for the fourth cyclone wave. The times for these events are January 1, 1997 18Z (top) and January 2, 1997 18Z (bottom). This is a water vapor satellite image for January 1, 1997 at 18Z. The fourth cyclone wave (CW #4) is approaching the western United States. The green lines indicate the locations of our cross sections (X-SECT). The first line is along the 39 th Parallel between 135 and 115 West Longitude and the second line is on the 35 th Parallel between 135 and 115 West Longitude. WP-TMP indicates the location of the western Pacific tropical moisture plume for this cyclone wave. This satellite image is the same as above except the date is January 2, 1997 at 18Z. The cross section lines remain unchanged. CW #4 has moved past Nevada and is moving towards the Rocky Mountains. The eastern Pacific tropical moisture plume (EP-TMP) is more evident across from Baja California towards Arizona and Utah. The 300 hPa reanalysis isotachs (m s -1 ) are presented here for January 1, 1997 at 18Z. The mid-tropospheric front (~500 hPa) is shown relative to the wind field. A surge of cold air is located upstream of the front as it begins to dip southward. The front itself is located near the jet's right exit region. This is X-SECT #2 from the line in the satellite image. The mid level cold front is beginning to show in this cross section, but still a distance to the west. The deep moisture pattern is generally more shallow compared to the north, but there is a good signal of 80%+ relative humidity near Bakersfield, California (BFL). This is X-SECT #1 from the line in the satellite image. Theta-E (K) lines are in red, while relative humidity (%) lines are in blue with color fill from 50%-100%. The mid level cold front is shown from about 125° W to just east of Reno, with the moist air ahead and the dry air behind it. The moisture that produces the flooding rain that is affecting the Reno area is shown by the cloud illustration as well as a 90%+ relative humidity signal that extends above 700 hPa. This is the 700 hPa reanalysis isentropic field (K) and wind field (barbs - m s -1 ). The circle shows where a mesoscale convective system (MCS) appears and produces a burst of precipitation for Reno for this time. A warm moisture tongue (WMT) is apparent to the east of Reno and this feature contributes to this burst of flooding rain. This image is the similar to the one above except the time is for January 2, 1997 18Z. The mid level cold front is located to the south of Lake Tahoe and San Francisco. The front is still located in the right exit region of the jet. Compared to 24 hours earlier, the moisture profile is more shallow and the 90%+ signal is not nearly as strong. However, this same signal is at Reno and is producing one of its last heavy precipitation bursts before the low-level cold front does arrive at Reno and produces more of a subsiding pattern. This cross sections shows a deeper moisture profile than 24 hours ago. The mid level cold front is still a couple of hours west of the California coastline. Once again, a high relative humidity signal (90%+) is approaching BFL. The MCS signal is a little more indistinguishable this time. From our analysis with the cross section earlier, there is not as much moisture as before but enough to produce a heavy burst of precipitation. The WMT is not as pronounced as before, but a small ridge is present and it appears to be oriented back towards the Sierra Nevada mountain range to the west.
Michael Kaplan, Phillip Marzette and Christopher Adaniya Division of Atmospheric Sciences // Desert Research Institute // University of Nevada-Reno Part 3: Mesoscale Overview 1996-1997 Reno Flood Background This poster is the third of the series about the features of the 1996-97 flooding event to affect northern Nevada and California. This poster will explain the mesoscale features and processes that take place with this flooding event in the time frame of about 6 to 12 hours. The illustrations below are of horizontal (above) and vertical (below) cross sections centered near Reno, Nevada. The horizontal cross section has the vertical motion field in the background. Dashed lines represent rising motion and solid lines sinking motion (μb s -1 ). We are looking at how two elevated cold fronts (CF-blue) and a thermal ridge (TR) influence our flooding event. The vertical cross section will show a similar analysis. The cross sections in the poster are all on the 39 th Parallel from 135° West Longitude to 115° West Longitude. The background field is the same as the last poster, utilizing the equivalent potential temperature and relative humidity fields. The times for these events are January 1, 1997 18Z, January 2, 1997 03Z, 15Z, and 21Z. In this image, the first heavy precipitation event begins near Reno, Nevada on January 1, 1997 18Z noted by our rain symbol in light blue. The yellow circle shows the location of our mesoscale convective system (MCS) associated with convective instability. We derive the first cold front (CF #1) from the 500 hPa potential temperature field and a thermal ridge (TR) from the 700 hPa equivalent potential temperature field. The location of the 300 hPa jet streak is shown in white over southern Oregon. 9 hours later on January 2, 1997 03Z, the TR and CF #1 become juxtaposed east of Reno. The leading edge of the convective instability moves east of Reno. The ascent which organized this rain event has created a cold pool and that cold air extends towards Sacramento, California. Our second cold front is visible to the northwest of Reno. This front is oriented across the flow instead of along the flow like the first front. On January 2, 1997 15Z, the thermal ridge is about the same position as CF #1. As for the second cold front, another heavy precipitation event is shown near Lake Tahoe just behind of the front. The precipitation is also located in the right exit region of the jet streak. 6 hours later, all of the features have propagated to the southeast. The heavy rains are nearing their conclusion at Reno and CF #2 has propagated east of Reno with colder air and subsidence in its wake. This is the first vertical cross section at January 1, 1997 at 18Z. The two locations of the fronts are shown and the heaviest precipitation and the largest magnitude upward vertical motion (black arrow) is encompassed in the white circle representing our convective instability. The second cold front is now visible in the cross section and this front is drying the air behind it substantially. A second burst of precipitation is also present near the Blue Canyon area along with strong upward vertical motion. The cold pool begins to develop in the San Joaquin Valley to the south of the cross section. 12 hours later, CF #1 and the TR are moving to the east and are becoming occluded. The heavy precipitation is still at Blue Canyon, CA as well as the vertical motion. CF #2 is still a little bit west of the California-Nevada border. The warm moist air at mid levels is associated with a thermally indirect circulation. This type of circulation is typical within the exit region of the jet shown above. At January 2, 1997 21Z, the precipitation and CF #2 moves east of Reno. The vertical motion is not as strong as the other times, especially near Reno, where the air experiences more of a sinking pattern.
Developed by I. Observing Modes of Convection Different types of thermodynamic and terrain induced processes can lead to various modes of convection. A forecaster might need to vary their prediction based on these parameters. These changes may result in a few hundredths of an inch of rain to several feet of snow. Radar image of conditional symmetric instability for March 3, 2006 ~8:15am PST Radar image of flooding event for December 31, 2005 1:00pm PST Radar image of heavy snow event for January 8, 2005 2:00pm PST Do we have strong veering wind profile aloft? Significant convective event. YES Is dθ/dz < 0 and are dθ lines more steep than m g lines? YES Strong case for conditional symmetric instability. Isolated, upright convection. Other modes of slantwise convection. NO III. Decision Tree for Different Forecasts The use of computer learning and intelligence is important for making an accurate forecast as depicted in the flowchart to the lower right. With input from the forecaster about what to look for when forecasting various convective modes, the computer decides what the best forecast is for that time. What does this mean? ●The forecaster observes various types of events and decides in their mind what dynamic features would be involved. ●The use of an adaptive grid model, such as OMEGA will simulate the smaller scale features in the atmosphere more clearly as the grid will adjust to the weather event itself instead of having the event adjust to the grid. ●The decision tree will help the computer learn more about types of convection and the processes behind these circulations. With the aid of an adaptive grid model and the forecaster inputting ongoing changes in these circulations, the computer takes the approach of case-based reasoning and the computer becomes more effective in determining which mode of is occurring and convection can properly be predicted. ●The cycle among these three components continues until the forecaster can model the atmosphere accurately. How Cognitive Information Processing Can Improve Weather Forecasts. Phillip Marzette // Division of Atmospheric Sciences // Desert Research Institute // University of Nevada-Reno II. Numerical Models Employing Grid Adaptivity Ideally we want to capture the small scale flow and the interaction and influence upon the larger flow. Adaptivity allows for an increase in resolution to better capture local topography or certain physical features of the atmospheric circulation at smaller scale. It eliminates the need for a nesting method. Grid points are added or removed to increase or decrease resolution in specific areas. Computer Information Processing (Case-Based Reasoning) The OMEGA grid can adapt to (a) the topography, (b) shorelines, and (c) the weather event existing at the time of initialization (Hurricane Linda). The resulting grid is seen in (d). The adaptive grid model will be effective at collapsing to the scale of differing convective modes such as a hurricane.
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