4.5: Alternative Text Descriptions for Investigation 4
- Page ID
- 42629
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Figure 4.2.1: Temperature vs. Time for De Anza College
A line graph titled “Temperature (°F) vs. Time (PST)” from De Anza College Weather Station. The horizontal axis represents time in hourly increments from 12:00 AM to 11:00 PM (Pacific Standard Time). The vertical axis represents temperature in degrees Fahrenheit, ranging from 40°F to 65°F.
The graph shows a general pattern where temperatures start near 47°F at midnight, decrease slightly to around 43°F between 5:00 AM and 7:00 AM, then steadily rise to a peak of approximately 64°F around 1:00 PM. After that, the temperature gradually decreases through the evening, dropping to around 48°F by 11:00 PM. This data illustrates a typical daily temperature cycle with cooler early morning temperatures, a midday peak, and a decline in the evening.
Figure 4.2.2: Temperature, Dew Point, and Relative Humidity vs. Time for Moffett Field, California.
A line graph titled “Mountain View, Moffett Field (KNUQ)” showing weather data over a 24-hour period on January 24, 2019. The horizontal axis displays date and time in Pacific Standard Time, marked at two-hour intervals from midnight (00:00) to the next midnight (00:00). The left vertical axis shows temperature in degrees Fahrenheit, ranging from 35°F to 75°F. The right vertical axis shows relative humidity in percent, from 30% to 95%.
Three separate lines represent:
- 2.0m Temperature: Starts around 46°F at midnight, slightly decreases to around 44°F by sunrise, then rises sharply between 09:00 and 12:00 to reach a peak of about 72°F around midday. The temperature remains steady in the early afternoon, then gradually drops through the evening, reaching about 50°F by the end of the day.
- 2.0m Dew Point: Begins around 40°F and shows minor fluctuations through the early morning. It slowly rises, peaks just below 50°F around 10:00–12:00, then remains fairly stable, ending the day slightly above 40°F. The dew point consistently remains lower than the temperature line, indicating drier air in the warmer part of the day.
- 2.0m Relative Humidity: Starts near 65% just after midnight. It declines sharply in the late morning as temperature rises, reaching a low point near 35–40% around midday. It then rises again in the late afternoon and evening, peaking around 75–80% by the end of the day.
The graph shows the relationship between rising temperature and falling relative humidity during daylight hours, with the opposite trend occurring at night. Dew point shows smaller variation, reflecting more gradual changes in atmospheric moisture. Together, the data illustrate a typical daily weather cycle with warmer, drier midday conditions and cooler, more humid nighttime conditions.
Figure 4.3.1: Cloud in a Bottle
A clear plastic bottle partially filled with water. The bottle has a blue screw-on cap. Inside the bottle, there is a vertical black strip that functions as a temperature strip or thermometer, displaying numbers that indicate temperature in degrees Celsius and Fahrenheit. Small droplets of condensation are visible on the inside surface of the bottle above the water level. The water appears still and fills the lower half of the bottle. The thermometer strip shows temperature markings ranging approximately from 18°C to 29°C (about 64°F to 84°F).
Figure 4.4.1: Surface Observations for Continental United States
A weather map of the contiguous United States dated 04Z (UTC) on July 15, 2025. The map shows dozens of weather station plots distributed across the country. Each station plot displays coded meteorological data including temperature, dew point, wind speed and direction, sea-level pressure, and present weather conditions.
At each station:
- The temperature in Fahrenheit is typically shown in the upper-left corner.
- The dew point temperature in Fahrenheit is shown in the lower-left corner.
- Wind is indicated by a small line with barbs extending from a central circle, showing wind direction and speed in knots.
- Sea-level pressure in millibars, usually coded, is displayed nearby.
- Present weather symbols such as dots or other marks may appear near the station circle to indicate precipitation or visibility.
Across the map, temperatures vary widely: in the western states, temperatures are generally in the 50s to 80s; in the south and southeast, temperatures often exceed 80°F; and in the northeast and Great Lakes region, temperatures are mostly in the 60s to low 70s. Wind barbs show varied wind directions and speeds, with some stations reporting calm conditions (circle without a barb).
Dew point values vary but tend to be higher in the eastern and southeastern U.S., indicating more humid conditions, and lower in the western interior and mountain regions, reflecting drier air.
The map provides a snapshot of weather conditions across the continental U.S., useful for analyzing temperature distribution, humidity, and wind patterns at this specific date and time.
Figure 4.4.2: Upper-Air Observations for Blacksburg, Virginia
This is a Stüve diagram for Blacksburg, Virginia (station 72318) from 00Z on July 15, 2025. It shows how temperature and moisture change with height in the atmosphere. The vertical axis is air pressure, which decreases with height (from the surface near 1000 mb to the upper atmosphere near 100 mb). The black lines represent the temperature and dew point at different altitudes.
The diagram also shows wind barbs on the right, which tell us wind direction and speed at various levels.
The main features necessary for this investigation are below:
The temperature and dew point lines are close together near the surface, meaning the air is humid near the surface, and again at approximately 900 mb, 725 mb and 640 mb.
Overall, this sounding shows warm, moist, and somewhat unstable air—conditions that could support thunderstorms if lifting mechanisms are present.
Figure 4.4.3: Upper-Air Observations for Oakland, California
This is a Stüve diagram for Oakland, California (station 72493), from 00Z on July 15, 2025. It displays how temperature and moisture change with height in the atmosphere, using pressure (in mb) as the vertical axis. Temperature and dew point profiles are shown in black lines. Isotherms are vertical, and pressure decreases with height from the surface (1000 mb) to the upper atmosphere (100 mb).
Wind barbs are shown on the right side and indicate wind speed and direction at different altitudes. Winds are generally weak and variable in direction throughout much of the atmosphere.
The main features necessary for this investigation are below:
The temperature and dew point lines are widely separated through most of the profile, showing dry air from the surface to upper levels. Winds are light and show little shear. The environment is strongly stable, with no signs of convective activity or instability.