# Introduction to PO (Coastal Ocean and Semi-enclosed Ocean)
> Instructor: Yiing-Jang Yang [time=April 22]
## Coastal process
include:
1. Effective of rivers
1. Coastal upwelling: topography, stratification, shoreline
1. Upwelling could induce red tide
1. Shelf waves: costal trapped wave, e.g. seiches and Kelvin wave
1. Seiche induced by local storm (typhoon or strong surge)
1. Edge wave: trapped wave along shoreline and induced by for foreign storm

### coastal upwelling
Ekman transport: to the RHS of the current. Thus, a upwelling is needed for continuity
### red tide
Upwelling or river discharge provided rich (nutrient-filled) water. Lots of phytoplakton grow

### Rip current
- may reach 3m/s
- induced by braking wave (converge of longshore current)
- Structure: feeder $\rightarrow$ neck, head $\rightarrow$ escape, (mushroom shaped)
- associated with dirty water (sand...)

> Instructor: Yiing-Jang Yang [time=April 29]
### Shoreline Erosion
More intense in the cape area
### Semi-enclosed Sea
#### Artic Ocean
> $9.5\times 10^6$ km^2^, 1/3 shallow water

**Bering Strait**: to Pacific, narrow (85 km) and shallow (45 m)
**Fram Strait**: to Atlantic, wide (450 km) and deep (3000 m)
**Lomonosov Ridge**: at the central (Canadian Basin in the Pacific side, Eurasian Basin in the Atlantic side)

* Covered by ice (3~5 m; max: 10~20 m), 20% open water in the summer
* <font color="#f00"> latent heat $\ll$ sensible heat </font>(LH: windspeed & humidity; SH: temperature difference)
* Salinity: 2~20 psu

#### Mediterranean Sea
**Stait of Gibraltar**: to Atlantic, wide 12 km, deep 300 m.
* Sill in the central (400 m in depth, shallowest)
* Basin depth: 2500 m
* Evaporte > rainfall
* **Model water**: 13.5 ℃, 38.5 psu (warm and salty)
* Mistral and cyclonic circulation
* deep convection, downwelling (5 cm/s), upwelling (1 cm/s)
#### Black Sea
**Bosphorus Strait**: to Aegean Sea, narrow (1 km) and shallow (60 m)
* Mediterranean water flow in Black Sea in lower layer; Black Sea flow out in upper laye
* Black Sea was a fresh lake at last ice age
#### Japan Sea / East Sea

#### South China Sea
**Luzong Strait**: width 300 km, depth 3000 m
* Transition in May and September
* summer flows from south to north; winter flows from north to south
* positive wind stress curl (pumpimg); clockwise, sinking
* monsoon cause tilting