Where would Christchurch be 100 million years in the past? 100 million years in the future?

To begin, let's look at Christchurch, New Zealand 100 million years in the past. According to this map, the entire island of New Zealand is in the polar region. It is also much closer to larger land masses. This would have huge effects on the climate. The area would receive little to no precipitation and the annual temperatures would drop over 40 degrees Celsius. Also, the temperature variation of the seasons would increase from an average of 15 degrees Celsius to an average of 40 degrees Celsius. This would happen because the climate of the island would not be controlled by the ocean like it is today. This region would only be influenced by polar continental air masses. The ocean would still have an impact but there are no warm currents near the south pole. A climograph for this location at this time would look something like this...



 A climograph of Christchurch so a much smaller diurnal temperature variation as well as much high rainfall levels given that is is now a maritime climate, instead of polar.

  Now, take a look at where Christchurch would be 100 million years in the future. This map is based on continental drifts from the past and estimations of where it would lead in the future. This is also based on the assumption that Earth will still exist that far into the future. As you can see, this map predicts New Zealand will move so far north that is will be cut in half by the Equator. This would also shift the climate drastically. With much warmer water surrounding the island, rainfall levels would nearly quadruple. Moving closer to large land masses would also assist in the rise of rainfall. Being this close to the equator and receiving this much rainfall would contribute greatly to the reduction in variation of diurnal temperatures in the area. The humidity would skyrocket; not that it's low currently, but it would be significant. Given higher rainfalls and steady temperatures, a climograph of the regions future would look similar to the one below...

Christchurch, and New Zealand in general, has made and will make some very significant travels in its time. It managed to make is from the south pole, up to the mid-latitudes of the southern hemisphere, and will just make it to the northern hemisphere. It is a place that will experience several climates throughout its time; except continental. This island seperated from the pack and will not rejoin a continent for a minimum of 100 million years. 

Reflection #2 - Christchurch, New Zealand vs. Ranohira, Madagascar

I chose Ranohira, Madagascar because it is similar in ways to Christchurch, but very different. Both locations are on a large island off the west coast of a large continent in the Southern Hemisphere. Ranohira differs in three major ways: 1 - it is much closer to Africa than New Zealand is to Australia, 2 - it is about 20 degrees closer to the equator than Christchurch,  3 - it is much further away from the coast, despite being an on an island.

The distance off a large continent makes all the difference in the world regarding the climatology of an island. Christchurch, under the Koppen/Geiger scheme of climate classification, is Cfb (marine west coast climate) while Ranohira is Cfa (humid subtropical climate). The major difference here is the overall heat in the area. Being close to the equator, Ranohira has much hotter summers and relatively hotter winters. Both places receive a lot of precipitation.

 

Christchurch is much more developed than Ranohira, therefore urban heat island effects are far more prevalent. Christchurch is also in the rain shadow of the Southern Alps while Ranohira is not influenced by any mountain range. However, Ranohira is much higher so the climates a similar.

Climatology

The Koppen/Geiger scheme of climate classfication defines the majority of locations in New Zealand, including Christchurch, as Cfb. Cfb stands for humid mid-latitude/marine west coast climate with mild winters. The westward coast of a continent has a different climate than the eastern coast due to incoming winds and that air heating over landmass. Since New Zealand is such a small landmass, the air has no time to heat while crossing from the east coast to west coast, where Christchurch is located. The factor that causes the west coast to be slightly drier is the ornographic uplift from the Southern Alps. This mountain range slows the passage of cyclonic storms allowing them to linger over the east coast and drop more rain. As a Cfb, Christchurch never really has a "dry" season; the rain simply decreases. However there is a significant change in temperature of the seasons. 

            Being an island, New Zealand is dramatically affected by the oceans. Christchurch is very close to the coast but the urban heat island effect is very strong here because it is in a valley. The Port hills lie to the East, separating the Bank’s peninsula. Being in this valley also allows for ponding and the clouds to roll just over the surface of Port Hills. I have mentioned before that New Zealand is known as Aotearoa, or Land of the Long White Cloud…this is why.

Reflection: Christchurch, NZ and Chicago, IL

Christchurch, New Zealand is located at 41 degrees South of the equator and Chicago, IL is located at 41 degrees North of the equator. Christchurch is on the eastern coast of New Zealand, located far from any continental air masses, affected only by maritime tropical air masses. Chicago, IL is landlocked in the northern Mid-West of the United States, affected by both cold, dry continental polar air masses from Canada in the winter and maritime tropical air masses from the Gulf of Mexico in the summer. These locations are similar in the respect they are both located in the temperate zones of their respective hemisphere. This allows for large temperature swings in both locations, granted Chicago's are a touch more drastic. The graphs below show similar curves in shape but Chicago's difference between winter low's and summer high's are very different. 

While Chicago is landlocked, it's located at the southern tip of Lake Michigan making for higher humidities than other states in the Mid-West. The humidity is similar to Christchurch. This is because Christchurch is in the valley of the Southern Alps, which lie to the west. Most of the moisture is sucked up by the mountains and the West coast of the island. They both have urban heat island effects but Chicago's is much more noticeable.

Chicago

Christchurch CoastChristchurch City

Air Masses

Christchurch is typically influenced by maritime air masses. These masses flow in from the east and loose moisture as the flow over the Southern Alps that lie east of the city. Most of the precipitation is dumped on the mountains as snow in the winter and rain the summer/spring/fall. Since New Zealand is an island nation there is not a huge difference between the moisture on either coast but it is significant enough to call the western coast drier. As you can see in the map below, taken from WeatherUnderground, Christchurch is engulfed in low-lying clouds (Blue and Gray). New Zealand is named Aotearoa by the native Maori people. This name means "land of the long white cloud" and properly called so because the country spends much of its time with cloud cover that never seems to end. These clouds lie so low because they are very dense with moisture due to the surrounding ocean. There is not enough land mass for continental air masses to form and this creates a temperate climate that promotes a vast plant species.

Introduction

Christchurch, New Zealand is the largest city on the South Island of the country. It is located at 41° South and 174° East. This location is between the Tropic of Capricorn and the Antarctic Circle placing it in the temperate zone of the southern hemisphere. Although it has a dry, temperate climate, Christchurch is dominated by maritime tropical air masses from the ocean surrounding New Zealand. Christchurch lies on the Eastern Coast of New Zealand just next to the Pacific Ocean, in the valley of the Southern Alps to the West. According to the weather station I will be using for most of my information (ICHRISTC10), the temperatures vary from 44°F to 94°F in the summer, from 36°F to 81°F in the fall, from 25°F to 69°F in the winter, and from 32°F to 81°F in the spring. It is important to note that the months involved in the season are opposite since the city is in the southern hemisphere. Also, these temperature ranges are an average of the data collected over the past five years.