Transcript for:
Understanding Wet and Dry Climates

hi everyone yesterday we went over the factors that affect climate today we're going to be looking at climate types let me get through this and get going right away um so we talked about the difference between weather and climate yesterday excuse me and remember weather is the condition of the atmosphere in an area for a short period of time what we're looking at is climate which is those patterns that develop over a long period of time and so they they are kind of grouped into what we call climate biomes or climate types i'm going to go real quick here through uh just the wet and dry climates and uh that'll be it for today so let's um let's talk about uh the the wet climates basically uh hot and wet is what they'll be um tropical rainforest and tropical wet dry you'll see tropical rainforest sometimes called tropical wet this is a very hot and rainy climate when you think of this what i think with all of these that really helps is if you can kind of get a mental picture or think of a place in the world it's going to help you kind of get that mental picture of what the landscape looks like but anytime we look at climate there are four things that you need to consider uh uh temperature precipitation natural vegetation and soil uh we're gonna be doing a climatograph here uh for an activity and that gives you a a pretty good idea of what the climate is in an area because the two most significant are going to be temperature and precipitation but it's not a complete picture really to have that complete picture you also need to include vegetation and soil so um wet climates tropical rainforest is generally going to be centered near the equator uh these are um your kind of jungle um climates if you will so i always say think of like the amazon rain forest or any tropical rain forest would be just that rain forest okay so it's going to be hot this says warm that's really should be hot it's going to be hot and rainy it's going to rain every day you know like those pop-up thunderstorms intense downpours and there is no distinct dry season it's pretty much this way year round uh high precipitation totals anywhere from 120 to 200 inches of precipitation annually in a tropical rainforest climate and so that causes what we call leaching of the soil it's going to wash out the nutrients still vegetation will grow very dense but it's going to be very thin and rocky soil and that dense vegetation is going to be what we call canopy vegetation where it forms so thick over the den the jungle floor that it creates like a canopy uh it'll even get so thick that it blocks out sunlight at times so tropical rainforest and tropical wet dry is the next one the big difference between this two is this distinct dry season that's what you have to remember tropical rainforest hot and rainy year round no distinct dry season in a tropical wet dry there is a distinct dry season from anywhere from four to eight months out of the year so for four to eight months out of the year it's going to be a lot like a tropical rainforest climate hot and rainy with high precipitation totals there and then the other half of the year the other four to eight months out of the year it's going to be more like a desert and so it will not rain much it'll still be hot but that dry season sets in and you get a different landscape so you can see right up here this is kind of your jungle landscape and then you have what i always think of is the serengeti plane in africa i think it's a fairly identifiable landscape and you get these tall or sparsely tall tropical deciduous trees sparsely populated with this tall grass around it's going to be this is in the dry season here that's why it's kind of a yellow grass if i were to show you a picture in the wet season the grass it would just be much greener if that makes sense soils are still leached but it's those tall grasses mixed with tropical deciduous trees that will make the landscape look completely different but the big difference here dry season in the wet dry no dry season in tropical rainforest okay still going to be found largely in uh near the equator as well all right your tropical drag or your tropical dry your dry climates um our desert and step um there are very few rules to these climates but one of them is here that step is always going to be found on the outskirts of desert so wherever you find a desert on the outskirts of it is going to be some step and that's because you're transitioning here from like a desert climate and then we'll transition to a step as it becomes a little more temperate and then mediterranean from there so let's go through these uh deserts i always say what's the largest desert in the world try to get that in your mind real quick right i bet a lot of you guys are saying the sahara desert and you're not technically wrong because it's the largest sandy desert in the world but because deserts are classified by precipitation um and less than 10 inches of precipitation makes it a desert technically antarctica is the largest desert in the world it's an arctic desert but what we're talking about here are these sandy deserts and you get a typical landscape looks like this it has a couple different things here that factor in what we call hamadas these flat sandstone plateaus and ergs and regs sandy dune covered areas and the desert pavement right here so it gets less than 10 inches of precipitation annually it's going to have large daily temperature ranges in the desert meaning that it's going to be really hot during the day and then because as you can see there's no cloud cover the heat escapes and at night it'll get below freezing even so it can get very cold at night sandy soils like humus that's humus not hummus hummus is the chickpeas that you put a you know pretzel chip in and eat and it's delicious hummus is decomposing organic material it's the decomposing uh dead animals plant life um fecal matter it gets decomposed down into the soil and makes it very fertile so what we're saying here when we say sandy soils like humus is that they lack fertility these are this is not a good soil any vegetation that's going to survive which will be very sparse you can see in this picture a few um very um you know small bushes um that are gonna have deep root systems thick bark to protect them from the harsh elements and thick and you know and thick leaves if you think about a cactus that grows here if you take the needles out of it it's very waxy it's a thick um you know waxy feel to it and that's to protect it in this harsh climate so that's a desert step again you're transitioning from desert to step would be next the big difference comes in precipitation 10 to 20 inches of annual precipitation whereas you get 10 inches so not a lot but still a little bit more you'll always find it around the outskirts of desert the soils are churnosum soil what shrinosum soil is you can kind of see the color of the soil in this picture it's a thick black earth that's actually very fertile so the difference in step is that it is a good soil you just don't get a lot of precipitation so it's still going to have not a lot of vegetation scrub grass that's often used for grazing livestock so people that live in the desert area will live on the outskirts in the steppe regions the a lot of pastoralism takes place here where the raising and grazing of livestock as a way of life is happening and they'll um you know graze them on these this desert scrub these clumps of grasses that you see in the picture so desert step big difference precipitation and bad soil in a desert actually good soil in a step okay and a little bit more precipitation 10 to 20 inches in a step last one here wrap up with this is a mediterranean climate um it's you know named kind of after where it's most predominant but you'll find this climate in southern california as well um you know but you're kind of your mental picture if you can think of italy or greece or southern california that's this the mediterranean climate that we're talking about here you're gonna have mild uh rainy winters um gotta text for have to turn those off so i have a meeting later anyway um so mediterranean long um mild okay i'm all out of sorts from the text so let's start again long hot drought-filled summers in a mediterranean climate and then short mild rainy winters okay so these long hot drought-filled summers will go it'll make this landscape extremely dry and then you have short mild rainy winters and so what happens a lot of times and if you think about it this time of year this is happening in southern california you hear a lot about it this time of year and currently is we have a lot to deal with a lot of um wildfires so it gets so hot and dry out there that somebody maybe flicks a cigarette and it and it sparks it or a thunderstorm lightning hits and sparks it because it's so dry and these wildfires will spread so quickly because of everything being so dry there's a general lack of humus in the soil and what you typically will see are these thickets of woody bushes that you see in the picture here that i'm kind of circling those are called chaparral they have large root systems and small leaves able to survive that drought-filled summer so that is the mediterranean the other thing with the mediterranean is typically um you have certain staples that will grow really well here like dates and olives you know grapes typically grow here and if you think about southern california right napa wine country dates our you know olives are in a a mediterranean salad so a lot of those staples come from here as well all right that is it um if you guys have any questions let me know i'll be obviously checking in with you guys on monday and tuesday making sure that you're understanding this and that uh and kind of reviewing and going back through it make sure we're good all right have a great thursday see you guys