Latitude and Climate
Content Statement 5: Latitude and longitude can be used to make observations about location and generalizations about climate. When you have completed this section, try the Latitude and Longitude Quiz Dividing that number in half, locations are between 0 and 90 degrees north or south The latitude of an area is one factor in the kind of climate the area might have. Relationship between geographical latitude and longitude and cloud-to-ground lightning flash .. Lightning activity as an indicator of climate change, Quart.
Atmospheric electricity, convective processes, lightning characteristics, Iberian Peninsula. Introduction Lightning activity is physically related with thunderstorms and it is a major cause of weather-related deaths, property damage and power system breakdowns. The combination of lightning data with radar observations may be used in the now-casting of convective systems Stern et al.
Lightning can be used to estimate convective rainfall i. Petersen and Rutledge, Because of the sensitivity of the global circuit to change in surface air temperature, it may also be used as an indicator of change in the global temperature Williams,; Reeve and Toumi, There is further interest in lightning activity, since it plays a fundamental role as a cause of natural forest fires in mid-latitudes i.
There are many works reporting the spatial distribution of flash characteristics.
For example, Orville, Orville and Silver and Orville and Huffines analysed the geographical distribution of cloud-to-ground CG lightning activity in the contiguous United States, Hodanish et al. These works show that the spatial distribution of CG-flash density is clearly related to the orography. Moreover, a tendency in the flash density to increase with altitude has been reported by several authors i.
Reap, in the United States; Pinto et al. The relationship of flash characteristics with geographical latitude and longitude is less investigated. Mackerras and Darveniza and Mackerras et al.
These works suggest that flash density decreases with latitude. Orville found a strong dependence between polarity and latitude in the contiguous United States.
Latitude and Longitude - Windows to the Universe
Orville and Pinto et al. In this work we have considered the Iberian Peninsula and analysed the relationship between geographical latitude and longitude and three CG-flash characteristics: This lightning detection network uses ALDF model T and is similar to those used in other countries.
Some characteristics of the lightning detection network have been described by Martin and Rivas et al. It can only detect CG-fiashes.
The system detect CG-flashes through the signal produced by the magnetic field of a lightning flash. The direction of the flash is determined from the signals from two or three sensors. Thus, CG-flashes can be detected in areas where there are no sensors. However, the number of detected flashes will decrease as the distance from the perimeters of the lightning detection network increases. In particular, distant weak flashes will not be detected. Detection efficiency is defined as the ratio between the number of detected flashes and the actual number of flashes.
Since there are no sensors located over Portugal, we expect a lower detection efficiency in this country than in Spain. However, as Portugal is close to the perimeter of the lightning detection network, it is assumed that the diminution of detection efficiency is low.
The data set covers the years The results appear in Figure 2. Figure 2a shows a clear relationship between flash density and latitude. The correlation coefficient is 0. The bilateral significance of this correlation is 0.
This may be explained as an orographic effect of the Pirineos. This is the most relevant mountain range in the Iberian Peninsula and the orographic forcing causes an enhancement in convection. As a consequence, the highest lightning activity is always fixed to the Pirineos, as reported by Rivas et al.
Latitude and Climate
Neglecting this maximum associated with the Pirineos, it is apparent that the flash density increases with latitude. This relationship between flash density and latitude is different from the one reported by other authors at both global and local scales Mackerras and Darveniza, ; Mackerras et al. Several studies show that lightning activity is mostly affected by the moisture content e. Thus, it is expected that the lightning activity decreases as the humidity content decreases.
The southern Iberian Peninsula is a dry area and, as a consequence, the lack of moisture in this zone may partly explain the above mentioned behavior. A tendency of flash density to increase with altitude has been reported by several authors Reap, ; Pinto et al.
This fact may also contribute to explain the relationship between flash density and latitude which is found in the Iberian Peninsula. The CG-flash density as a function of longitude appears in Figure 2b. From this longitude up to the eastern limit there is not a clear relationship between flash density and longitude. Longitude 3W corresponds with that of the Mediterranean coast, where thunderstorms are frequent, due to the effect of the moist warm air from the Mediterranean sea.
In consequence, the relationship between CG-flash density and longitude seems to reflect the relevance of the Mediterranean sea on lightning activity in the Iberian Peninsula. In order to analyse the relationship between polarity and latitude and longitude, we have averaged the percentage of positive flashes over longitude and latitude respectively.
The results are shown in Figure 3.
Figure 3a shows the percentage of positive flashes as a function of latitude. The correlation coefficient is This correlation is significant bilateral significance 0. A large number of positive flashes has been observed in association with the trailing stratiform region of mesoscale convective systems MCS e.
Rutledge and McGorman, ; Rutledge et al, The latter is in agreement with other studies. Orville found a strong latitude dependence in the contiguous United States and suggested that this dependence is an effect of temperature. The charge separation is a function of the temperature e. Dong and Hallett, and, as a consequence, with increased latitude the charged region of the cloud will be closer to the surface. Under this condition, more positive streamers coming from the upper positive charge center of the cloud can reach the ground, increasing the percentage of positive flashes.
Figure 3b shows the percentage of positive flashes as a function of longitude. In this case, the correlation coefficient is only Longitude is the measurement either east or west from the Prime Meridian, a line of longitude which runs between the poles and through Greenwich, England. Longitude increases as you leave the Prime Meridian 0 degrees going east 0 to degrees and decreases as you head west 0 to degreesuntil they meet at degrees.
Why does the Prime Meridian go through Greenwich, England? It could be anywhere, but in the mids the Royal Observatory in Greenwich, England was well known for keeping time, and because the time is the same all along that line of longitude, it was decided that the Prime Meridian would go through Greenwich.
Here's an example of the latitude and longitude of a specific location. This means New York, NY is approximately 41 degrees north of the equator and approximately 74 degrees west of the Prime Meridian.
A region's latitude has a great effect on its climate because latitude determines the amount of solar energy a region receives. Low latitude locations, on or near the equator, are called the tropics.
It's warm there because roughly the same amount of sunlight is received year-round. High latitude locations, at or near the poleshave a cold, polar climate. The closer you are to one of Earth's poles, the less sunlight there is during winter days. Mid-latitude climates in the areas between the tropics and polar regions have several distinct seasons throughout the year because the amount of sunlight changes from summer to winter.